Automatic Transaxle Servicing Buick Century VI

APPLICATION

TRANSAXLE APPLICATION

IDENTIFICATION

Transaxle has a metal identification plate or Service Replacement Transmission Assembly (SRTA) plate attached to rear face of transaxle. (Scheme 193) Transaxle RPO codes are MN7 or M15. Century models, use RPO code M15. Regal models use RPO code MN7 or M15. The MN7 is a heavy duty model and has a 10.2" (258 mm) torque converter. The M15 model has a 9.6" (245 mm) torque converter.

Scheme 193

Scheme 194

SERVICE INTERVALS

Change the ATF and filter every 50,000 miles if the vehicle is mainly driven under one or more of these conditions

1. In heavy traffic where the outside temperature regularly reaches 90°F (32°C) or higher.
2. In hilly or mountainous terrain.
3. When doing frequent towing
4. Uses such as found in taxi, police or delivery service.

If the vehicle is not used under any of these conditions, change the fluid and filter every 100,000 miles.

CHECKING FLUID LEVEL & CONDITION

1. Start the engine and allow the engine to idle until the transaxle has reached 180-200°F (82-93°C). Depress the brake pedal and move the shift lever through the gear ranges, pausing a few seconds in each gear. Is the fluid Red or Light Brown? If so, go to step 4 . If not, go to next step.
2. Does the fluid have a burnt odor or a Dark Brown color? If so, go to step 11 . If not, go to next step.
3. Does the fluid have a cloudy or milky appearance? If so, go to step 10 . If not, go to next step.
4. Check the fluid level. The vehicle must be level, with the engine running and the shift lever in the Park range. Check both sides of the fluid level indicator, and read the lower level. The proper fluid level should be in the middle of the cross-hatch. Is the fluid level too high? If so, go to step 9 . If not, go to next step.
5. Is the fluid level low? If not, system is okay. If so, go to next step.
6. Add DEXRON-III(R) ATF in increments of 17 ounces (0.5L) until the fluid is in the middle of the cross-hatch. Check both sides of the fluid level indicator, and read the lower level. Did you add more than 51 ounces (1.5L) to the transaxle? If not, go to step 9 . If so, go to next step.
7. Check for external leaks. Did you find any leaks? If not, go to step 15 . If so, go to next step.
8. Correct the leak condition. Did you correct the leak condition? If so, go to step 15 .
9. Remove any excess fluid to the proper level, the middle of the cross-hatch. Is the fluid level satisfactory? If so, system is okay.
10. The transaxle is contaminated with engine coolant. Replace the cooler. Is the replacement complete? If so, go to step 12 .
11. Drain the fluid to determine if the fluid is contaminated. A very small amount of material in the bottom pan is a normal condition, but large pieces of metal or other material in the bottom pan require a transaxle overhaul. Was the fluid contaminated? If so, go to step 13 . If not, go to next step.
12. Overhaul the transaxle. See appropriate OVERHAUL article. Is the overhaul complete? If so, go to next step.
13. Flush the cooler. See «OIL COOLER FLUSHING»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__oil-cooler-flushing-flow-test) . Has the cooler been flushed? If so, go to next step.
14. Change the fluid and the filter. See «DRAINING & REFILLING»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__draining-refilling) . Is the procedure complete? If so, go to next step.
15. Add new fluid to the proper level, in the middle of the cross-hatch. Is the procedure complete? If so, system is okay.

RECOMMENDED FLUIDS

Manufacturer recommends DEXRON-III(R) ATF. Fill transaxle with appropriate quantity. See FLUID CAPACITIES .

FLUID CAPACITIES

TRANSAXLE FLUID CAPACITIES (1)

DRAINING & REFILLING

1. Raise and support the vehicle. Place a drain pan under the transaxle bottom oil pan. Remove the oil pan bolts (23) from the front. (Scheme 195) Remove the oil pan bolts (23) from the sides. Loosen the rear oil pan bolts (23) approximately 4 turns.
2. Use a rubber mallet to lightly tap the oil pan or use a screwdriver to pry the oil pan loose. Allow the fluid to drain. Remove the remaining oil pan bolts (23).
3. Remove the oil pan (24). Remove the oil pan gasket (25). Remove the filter (100). Remove the lip ring seal (101) pressed into the case only if replacement is necessary. Inspect the oil pan and the filter screen for the following foreign material: Inspect for metal particles. Inspect for clutch facing material. Inspect for rubber particles. Inspect for engine coolant.
4. Determine the source of the contamination if foreign material is evident. Correct the source of the contamination. Use solvent to clean the screen and blow-dry if reusing. Install a new seal (101). (Scheme 196) Install the filter (100). (Scheme 195)
5. Inspect the oil pan flange (1) for distortion. (Scheme 197) Replace the oil pan (1) if bent or distorted. Do not attempt to straighten. Inspect the washers on the bolts when service requires the removal of the bottom oil pan. Install a new bolt and washer assembly if the washer is inverted. (Scheme 198)
6. Use solvent to clean the case. Air dry the case. Use solvent to clean the oil pan gasket surfaces. Air dry the oil pan gasket surfaces. Ensure all traces of the old gasket material are removed.
7. Install the oil pan gasket (25). (Scheme 195) Install the oil pan (24). Install the oil pan bolts (23). (Scheme 198) Tighten the oil pan bolts (23) to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__torque-specifications).
8. Lower the vehicle. Fill the transaxle with appropriate fluid to proper level. See «RECOMMENDED FLUIDS»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__recommended-fluids) and «FLUID CAPACITIES»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__fluid-capacities). Place the gear selector in the Park position. Start the engine.
9. Run the engine at a slow idle. Do not race the engine. Adjust the fluid level. See «CHECKING FLUID LEVEL & CONDITION»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__checking-fluid-level-condition). Inspect for proper completion of the repairs. Inspect for fluid leaks.

Scheme 195

Scheme 196

Scheme 197

Scheme 198

OIL COOLER FLUSHING & FLOW TEST

Note. GM studies indicate that plugged or restricted transaxle oil coolers and pipes cause insufficient transaxle lubrication and elevated operating temperatures which can lead to premature transaxle wear-out. Many cases could have been prevented by following published procedures for transaxle oil cooler flushing and flow checking. This procedure includes flushing and flow checking the auxiliary oil cooler, if equipped. GM requires that oil cooler flushing and flow checking be performed whenever a transaxle is removed from the vehicle for service within warranty, including: Goodwin, SWAT, major overhaul, torque converter replacement and oil pump replacement.

Preparation

1. After the repair or replacement transaxle is installed in the vehicle, do not reconnect the oil cooler pipes.
2. Remove the fill cap (9) on the Transmission Oil Cooler and Line Flusher (J-35944-A) and fill the flusher tank (4) with 20 oz. (0.6L) of flushing fluid using the measuring cup (6). Do not overfill. Install the fill cap (9) on the transmission oil cooler and line flusher and pressurize the flusher tank (4) to 80-100 psi, using the shop air supply at the tank air valve (9). (Scheme 199)
3. Connect the transmission oil cooler and line flusher discharge hose (5) to the oil cooler return pipe (top connector). Clip the discharge hose (5) onto the oil drain container. Attach the transmission oil cooler and line flusher to the undercarriage of the vehicle with the hook provided, and connect the flushing system feed supply hose (3) from the transmission oil cooler and line flusher to the oil cooler feed pipe (bottom connector).
4. With the water supply valve (1) on the transmission oil cooler and line flusher in the OFF position, connect the water supply hose (7) from the transmission oil cooler and line flusher to the water supply at the faucet. (Scheme 199)and (Scheme 200). Turn on the water supply at the faucet.

Scheme 199

Scheme 200

Initial Flush

1. Turn the transmission oil cooler and line flusher water supply valve (1) to the ON position and allow water to flow through the oil cooler and pipes for 10 seconds to remove any remaining transmission fluid. (Scheme 201) If water does not flow through the oil cooler and pipes, the cause of the blockage must be diagnosed and the plugged component must be repaired or replaced. Continue with the cooler flushing and flow check procedure once the blockage is corrected.
2. Turn the transmission oil cooler and line flusher water supply valve (1) to the OFF position and clip the discharge hose (5) onto a 5 gallon (19L) pail with a lid, to avoid splashback. (Scheme 202) Turn the transmission oil cooler and line flusher water supply valve (1) to the ON position and depress the trigger (8) to mix cooler flushing solution into the water flow. (Scheme 199) Use the clip provided on the handle to hold the trigger (8) down. The discharge will foam vigorously when the solution is introduced into the water stream.
3. Flush the oil cooler and pipes with water and solution for 2 minutes. During this flush, attach the shop air supply of 120 psi to the flushing system feed air valve (2) located on the transmission oil cooler and line flusher for 3-5 seconds at the end of every 15-20 second interval to create a surging action.
4. Release the trigger (8) and turn the transmission oil cooler and line flusher water supply valve (1) to the OFF position.

Scheme 201

Scheme 202

Back Flush

1. Disconnect both hoses from the oil cooler pipes and then connect them to the opposite oil cooler pipe. This will allow the oil cooler and pipes to be back flushed. Repeat steps 2 and 3 of the INITIAL FLUSH procedure. Release the trigger (8) of the transmission oil cooler and line flusher and allow water only to rinse the oil cooler and pipes for one minute.
2. Turn the transmission oil cooler and line flusher water supply valve (1) to the OFF position and turn off the water supply at the faucet. (Scheme 200) Attach the shop air supply to the flushing system feed air valve (2) on the transmission oil cooler and line flusher, and blow out the water from the oil cooler and pipes. Continue until no water comes out of the discharge hose (5).

Flow Check

1. Disconnect both hoses from the oil cooler pipes. Connect the oil cooler feed pipe (vertical/top connector) to the transaxle and the return pipe (horizontal/bottom connector) to the discharge hose (5). Clip the discharge hose (5) onto the empty oil drain container. (Scheme 202)
2. Confirm the transaxle is filled with DEXRON-III(R) ATF. See «CHECKING FLUID LEVEL & CONDITION»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__checking-fluid-level-condition). Start the engine with the transaxle in Park range and run for 30 seconds. A minimum of 2 qts. (1.9L) must be discharged during this 30-second run time. If fluid flow is greater than 2 qts. (1.9L) in 30 seconds, go to next step. If fluid flow is less than 2 qts. (1.9L) in 30 seconds, perform the following diagnosis: Disconnect the oil cooler feed line at the radiator. Connect the discharge hose (5) to the cooler feed line. Clip the discharge hose (5) to the empty oil drain container. (Scheme 202) Start the engine with the transaxle in Park range and run for 30 seconds. A minimum of 2 qts. (1.9L) must be discharged during this 30-second run time. Do the following according to the flow rate: Insufficient feed flow: inspect the transaxle. Sufficient feed flow: inspect the oil cooler return pipe and the oil cooler (and auxiliary cooler, if equipped).
3. Remove the discharge hose (5), reconnect the cooler feed and return pipes to the transaxle and refill the unit to the proper fluid level. Inspect the transaxle oil cooler pipe connections at the radiator, the auxiliary cooler (if equipped) and the transaxle for leaks.

Clean-up

Disconnect the water supply hose (7) from the transmission oil cooler and line flusher and bleed any remaining air pressure from the flusher tank (4). (Scheme 199) Remove the fill cap (9) from the transmission oil cooler and line flusher and return any unused flushing solution to its container. Rinse the transmission oil cooler and line flusher with water. Do not store the transmission oil cooler and line flusher with flushing solution in it. After every 3rd use, clean the transmission oil cooler and line flusher as described in the instructions included with the tool. Dispose of any waste water/solution and transmission fluid in accordance with local regulations.

ON-VEHICLE REPAIRS

Various components may be serviced without transaxle removal. For servicing of these components, see appropriate component under ADJUSTMENTS and/or REMOVAL & INSTALLATION . For additional information on servicing electrical components, see appropriate DIAGNOSIS article.

ADJUSTMENTS

PARK/NEUTRAL POSITION SWITCH

1. If a new Park/Neutral Position (PNP) switch has been rotated and the pin is broken or if using an old PNP switch, adjust the PNP switch. Place the shift shaft in the Neutral position.
2. Install the PNP switch to the mounting boss. (Scheme 203) Assemble the PNP switch mounting bolts loosely.
3. Use the Park/Neutral Switch Alignment Tool (J-41545) to align the flats of the shift shaft to the flats (1 and 2) on the PNP switch. (Scheme 204)
4. Install the PNP switch mounting bolts. Tighten the PNP switch mounting bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__torque-specifications).

Scheme 203

Scheme 204

SHIFT CABLE

Note. Adjust the shift cable while the transaxle manual control lever and the shift control lever are in the Neutral position only. Failure to do so may cause misadjustment.

1. Set the parking brake. Block the wheels. Disconnect the shift cables at both ends with the system in Neutral.
2. Push the adjuster up to the adjustment position until the cable housings separate. This releases the adjuster. (Scheme 205) Depress the adjuster clip once.
3. This mobilizes the adjuster housing toward the transaxle end fitting. Line up the end fittings so they slide together until you feel the parts cam together and lock.
4. Depress the adjuster clip completely. This locks the cable into its adjusted service position. Pull the conduit in the opposite direction to assure full system adjustment of the shift cable.
5. The horseshoe clip with the tab is flush when fully engaged. (Scheme 206)
6. Fully engage the conduit. The horseshoe clip with the tab is not flush when not fully engaged. Install the shift cable retainer and the wiring harness clip or wiring harness strap.

Scheme 205

Scheme 206

REMOVAL & INSTALLATION

Note. Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Note. Some removal and installation procedures may require the removal of engine and/or transaxle mounts. For procedures related to these components, see appropriate REMOVAL & INSTALLATION article.

Removal

1. Raise and support the vehicle. Remove the oil pan and filter. See «DRAINING & REFILLING»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__draining-refilling) under LUBRICATION.
2. Remove the accumulator bolts. (Scheme 207) Remove the manual 2-1 band servo cover bolts.
3. Remove the lube oil pipe from the front differential carrier internal gear lube hole. (Scheme 209) Remove the accumulator and the manual 2-1 band servo cover as a assembly. Remove the manual 2-1 band servo cover. Remove the manual 2-1 band servo. (Scheme 208)
4. To disassemble, inspect and service the accumulator and 2-1 manual servo, see appropriate OVERHAUL article.

Scheme 207

Scheme 208

Scheme 209

Installation

1. If disassembled, assemble the 2-1 band servo. See appropriate OVERHAUL article. Install the manual 2-1 band servo. (Scheme 208) Install the lube oil pipe to the front differential carrier internal gear lube hole. (Scheme 209) Position the manual 2-1 band servo cover and accumulator into place.
2. Install the manual 2-1 band servo cover bolts. Tighten the manual 2-1 band servo cover bolts to specification. Install the accumulator attaching bolts. Tighten the accumulator attaching bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__torque-specifications).
3. If removed, install the new filter seal. Install the filter. Install the oil pan. See «DRAINING & REFILLING»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__draining-refilling) under LUBRICATION. Lower the vehicle. Fill transaxle with appropriate fluid to proper level. See «LUBRICATION»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).

1. Disconnect the negative battery cable. Raise and support the vehicle. Disconnect the right drive axle from the transaxle. See appropriate AXLE SHAFTS article in DRIVELINE/AXLES.
2. Remove transaxle brace. See «TRANSAXLE BRACE»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Remove the vehicle speed sensor. See «VEHICLE SPEED SENSOR»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).
3. Remove the case extension housing bolts. (Scheme 210) Remove the case extension housing with axle seal and the O-ring. Inspect the case extension for the following conditions: Damaged or porous sealing surface for the case extension seal. Damaged or porous sealing surface for the vehicle speed sensor. Damaged or porous sealing surface for the right drive axle oil seal. Damaged or porous sealing surface for the case extension housing. Damaged or worn differential carrier bushing or output shaft bearing. Damaged bolt holes. Inspect the drive axle seal and replace if necessary.

Scheme 210

1. Perform a differential carrier end play inspection. See appropriate OVERHAUL article. If removed, install the drive axle seal. Install the case extension housing with the axle seal and the O-ring. (Scheme 210)
2. Install the case extension housing bolts. Tighten the case extension housing bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__torque-specifications). Install the vehicle speed sensor. See «VEHICLE SPEED SENSOR»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).
3. Install the transaxle brace. See «TRANSAXLE BRACE»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Connect the right drive axle to the transaxle. Install the right drive axle to the transaxle. See appropriate AXLE SHAFTS article in DRIVELINE/AXLES. Lower the vehicle. Connect the negative battery cable.
4. DO NOT overfill the transaxle. The overfilling of the transaxle causes foaming, loss of fluid, shift complaints, and possible damage to the transaxle. Fill transaxle with appropriate fluid to proper level. See «LUBRICATION»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Inspect for completion of the repairs. Inspect for fluid leaks.

1. Disconnect the negative battery cable. Remove the throttle body air inlet duct. Install the engine support fixture. See appropriate REMOVAL & INSTALLATION article. Remove the engine mount struts. Disconnect the transaxle wiring harness connector.
2. Raise and support the vehicle. Remove the left drive axle from the transaxle. See appropriate AXLE SHAFTS article in DRIVELINE/AXLES. Secure the drive axle to the steering knuckle/strut.
3. Remove the intermediate steering shaft pinch bolt and the shaft from the steering gear. See appropriate POWER RACK & PINION article in STEERING. Remove the 3-way catalytic converter pipe from right exhaust manifold.
4. Support the right and the left side of the frame with jackstands. See appropriate REMOVAL & INSTALLATION article. Remove the transaxle mount. See «TRANSAXLE MOUNT»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Loosen the engine mount lower nuts.
5. Loosen the right side frame bolts and remove the left side frame bolts. Adjust the jackstand to the lower left side of the frame. Position the drain pan under the transaxle.
6. Remove the case side cover bolts. (Scheme 211) Remove the case side cover pan (53). (Scheme 212) Remove the case side cover gasket (54). Clean the case. Clean the side cover gasket mating surfaces.

Scheme 211

Scheme 212

1. Install the case side cover gasket (54). (Scheme 212) Install the case side cover pan (53). Install the case side cover bolts (56-58). Tighten case side cover bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__torque-specifications).
2. Remove the drain pan from under the transaxle. Adjust the jackstand to raise the left side of the frame. Install the left and right side frame bolts.
3. Install the engine mount lower nuts. Install the transaxle mount. See «TRANSAXLE MOUNT»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Remove the jackstands from the frame. Install the 3-way catalytic converter pipe to the right exhaust manifold.
4. Install the intermediate shaft to the steering gear and the pinch bolt. See appropriate POWER RACK & PINION article in STEERING. Install the left drive axle to the transaxle. See appropriate AXLE SHAFTS article in DRIVELINE/AXLES. Lower the vehicle. Connect the transaxle wiring harness connector.
5. Install the engine mount struts. See appropriate REMOVAL & INSTALLATION article. Remove the engine support fixture. Install the throttle body air inlet duct. Connect the negative battery cable.
6. DO NOT overfill the transaxle. Overfilling will result in foaming, loss of fluid, and possible damage to the transaxle. Fill transaxle with appropriate fluid to proper level. See «LUBRICATION»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Inspect for fluid leaks.

1. Remove the case side cover. See «CASE SIDE COVER»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Remove the oil pump. See «OIL PUMP»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Remove the valve body bolts (374-381 and 384). (Scheme 213)
2. Remove the valve body (300) while keeping the spacer plate (370) with the transaxle. (Scheme 214) Remove the ball check valves (372 and 373) from the valve body. (Scheme 215)
3. Remove the spacer plate (370) and gasket. (Scheme 216) Remove the ball check valves (372) from the case cover. (Scheme 217) Inspect each check valve seat in the spacer plate (370) for excessive peening. (Scheme 218)
4. Place a ball check valve (372) on each seat and use a flashlight in order to look for visible light between the valve and the seat. Inspect all components removed from the transaxle. See appropriate OVERHAUL article.

Scheme 213

Scheme 214

Scheme 215

Scheme 216

Scheme 217

Scheme 218

1. Install the ball check valves (372) into the case cover. (Scheme 217) Use the (J-36850) Transjel(tm) to retain the ball check valves in their proper locations. Install the gasket and the spacer plate (370). (Scheme 216)
2. Install the ball check valves (372 and 373) into the valve body. (Scheme 215) Use Transjel(tm) to retain the ball check valves in their proper locations.
3. Install the gasket (371) and the valve body (300). (Scheme 214) Install the valve body bolts (374-381 and 384). (Scheme 213)
4. Tighten the valve body bolts as follows: M6 X 1.0 X 20 - 70 INCH lbs. (8 N.m). M6 X 1.0 X 30 - 106 INCH lbs. (12 N.m). M6 X 1.0 X 45 - 106 INCH lbs. (12 N.m). M6 X 1.0 X 55 - 97 INCH lbs. (11 N.m). M6 X 1.0 X 60 - 106 INCH lbs. (12 N.m). M6 X 1.0 X 65 - 106 INCH lbs. (12 N.m). M6 X 1.0 X 85 - 97 INCH lbs. (11 N.m). M6 X 1.0 X 90 - 97 INCH lbs. (11 N.m). M8 X 1.0 X 90 - 18 ft. lbs. (25 N.m).
5. DO NOT use impact type tools on the valve body or on the oil pump. Install the oil pump. See «OIL PUMP»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Install the case side cover. See «CASE SIDE COVER»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).

Remove the indicator. Raise and support the vehicle. Disconnect the 3-way catalytic converter pipe. Remove the fluid filler tube bracket bolt from the fluid filler tube bracket. (Scheme 219) Remove the fluid filler tube.

Scheme 219

Install the fluid filler tube seal in the transaxle. Position the fluid filler tube. Install the fluid filler tube bracket bolt through the fluid filler tube bracket. Tighten the fluid filler tube bracket bolt to specification. See TORQUE SPECIFICATIONS . Lower the vehicle. Install the indicator. Fill transaxle with appropriate fluid to proper level. See LUBRICATION . Inspect for fluid leaks.

Remove the case side cover. See CASE SIDE COVER. Disconnect the wiring harness assembly from the fluid temperature sensor. (Scheme 220) Remove the fluid temperature sensor.

Scheme 220

Install the fluid temperature sensor. (Scheme 220) Connect the wiring harness assembly to the with fluid temperature sensor. Install the case side cover. See CASE SIDE COVER.

1. Remove the case side cover. See «CASE SIDE COVER»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).
2. Disconnect the transaxle wiring harness. Remove the input speed sensor clip (441) from the case cover. (Scheme 221)
3. Remove the input speed sensor (440) from the case cover. Inspect the input speed sensor (440) for the following conditions: Damaged or missing magnet. Damaged housing. Bent or missing electrical terminals. Damaged speed sensor clip (441).

Scheme 221

1. Install the input speed sensor (440) into the case cover. (Scheme 221)
2. Install the input speed sensor clip (441) into the case cover.
3. Connect the transaxle wiring harness.
4. Install the case side cover. See «CASE SIDE COVER»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).

OIL COOLER HOSE/PIPES

Note. Allow sufficient clearance around the transaxle oil cooler pipes and around the hoses to prevent damage or wear which may cause fluid loss.

1. Raise and support the vehicle. Position the drain pan. Remove the lower radiator air deflector.
2. Perform the following procedures when removing the retaining ring and the oil cooler pipe from the quick connect fitting on the transaxle.
3. Pull the plastic cap back from the quick connect fitting and down along the oil cooler pipe about 2". Using a bent-tip screwdriver, pull on one of the open ends of the retaining ring in order to rotate the retaining ring around the quick connect fitting until the retaining ring is out of position and can be completely removed. (Scheme 222)
4. Remove the retaining ring from the quick connect fitting. Discard the retaining ring. Remove the retaining bracket bolt (5) from the transaxle oil cooler hose/pipe retaining bracket (1). (Scheme 223)
5. Remove the oil cooler pipes (3 and 4) from the oil cooler fittings (2). Remove the oil cooler pipes from the fittings at the radiator. (Scheme 224)
6. Remove the oil cooler hose/pipes from the retaining clip. Remove the oil cooler hose/pipes from the vehicle.

Scheme 222

Scheme 223

Scheme 224

Note. Do not reuse any of the existing retaining rings that were removed from the existing quick connect fittings. All retaining rings being installed must be new.

1. Install a new retaining ring into the quick connect fitting using the following procedure. Hook one of the open ends of retaining ring into one of the slots in the quick connect fitting. (Scheme 225)
2. Rotate the retaining ring around the fitting until the ring is positioned with all 3 ears through the 3 slots on the fitting. (Scheme 226) DO NOT install the new retaining ring onto the fitting by pushing the retaining ring. (Scheme 227)
3. Ensure that the 3 ears are seen from inside the fitting and that the ring moves freely in the fitting slots. (Scheme 228) Install the new retaining ring into the remaining quick connect fittings.
4. Install the oil cooler hose/pipes to the retaining clip. (Scheme 222) Ensure that the cooler line being installed has a plastic cap on each end that connects to a quick connect fitting.
5. If no plastic cap exists, or the plastic cap is damaged, obtain a new plastic cap and position on to the cooler line prior to the cooler line installation.
6. DO NOT use the plastic cap to install the oil cooler pipe into the fitting. Install the oil cooler pipe into the quick connect fitting at the radiator.
7. Insert the oil cooler pipe end into the quick connect fitting until a click is either heard or felt. (Scheme 229) Pull back sharply on the oil cooler pipe in order to ensure that the pipe is fastened into the quick connect fitting.
8. Install the plastic cap onto the fitting. (Scheme 230) DO NOT manually depress the retaining ring when installing the cap onto the fitting. Ensure that the cap is fully seated against the fitting.
9. Ensure that no gap is present between the cap and the fitting. (Scheme 231) Ensure that the Yellow identification band on the tube is hidden within the quick connect fitting.
10. A hidden Yellow identification band indicates proper joint seating. (Scheme 232) Install the oil cooler pipes (3 and 4) to the oil cooler fittings (2). (Scheme 223)
11. Install the transaxle oil cooler hose/pipes retaining bracket bolt (5). Tighten the bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__torque-specifications). Install the lower radiator air deflector.
12. Remove the drain pan from under the vehicle. Lower the vehicle. Fill transaxle with appropriate fluid to proper level. See «LUBRICATION»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Inspect for proper completion of the repairs. Inspect for fluid leaks.

Scheme 225

Scheme 226

Scheme 227

Scheme 228

Scheme 229

Scheme 230

Scheme 231

Scheme 232

On models with 3.4L engine, remove the throttle body air inlet duct. On models with 3.8L engine, remove air cleaner assembly. On all models, remove the line the pressure pipe plug (38). (Scheme 233)

Scheme 233

Apply (GM P/N 8654382) to the line pressure pipe plug. Install the line pressure pipe plug (38). (Scheme 233) Tighten the line pressure pipe plug to specification. See TORQUE SPECIFICATIONS. On models with 3.4L engine, install the throttle body air inlet duct. On models with 3.8L engine, install air cleaner assembly.

Note. Do not remove the 3 bolts which hold the pump together.

Remove the case side cover. See CASE SIDE COVER. Remove the oil pump bolts (205, 206 and 207). (Scheme 247) Remove the oil pump from the valve body. (Scheme 248) Inspect the oil pump.

Install the oil pump to the valve body. (Scheme 248) Install the oil pump bolts (205, 206 and 207). (Scheme 247) Tighten oil pump bolts as follows

1. M6 X 1.0 X 20 (205) - 70 INCH lbs. (8 N.m).
2. M6 X 1.0 X 85 (207) - 106 INCH lbs. (12 N.m).
3. M6 X 1.0 X 95 (206) - 106 INCH lbs. (12 N.m).

Install the case side cover. See CASE SIDE COVER .

1. Remove the case extension housing. See «CASE EXTENSION HOUSING»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Rotate the differential carrier until the end of the output shaft can be seen and the differential pinion shaft is in a horizontal position. (Scheme 234)
2. Place the Axle Removal Wedge (J-42562) between the end of the output shaft and the differential pinion shaft. Using a hammer, hit the end of the axle removal wedge in order to compress the output shaft compression ring and push the output shaft through the differential side gear.
3. Remove the differential carrier. Using snap ring pliers remove the compression ring from the output shaft. (Scheme 235) Be careful not to damage the bearing on the output shaft. (Scheme 237)
4. Remove the output shaft through the left wheel opening. (Scheme 236) Inspect the output shaft and the bearing for the following: A cracked or deformed bearing cage. Damaged bushing journals. Stripped splines. A damaged retainer ring groove.

Scheme 234

Scheme 235

Scheme 236

Scheme 237

1. Install the drive axle retaining ring and the output shaft differential inboard snap ring onto the output shaft. (Scheme 237) Install the fourth clutch bearing onto the output shaft.
2. Hold the front differential carrier in place and carefully install the output shaft into the transaxle through the left wheel opening. (Scheme 236)
3. Extend the output shaft through the differential side gear. Install the case extension housing. See «CASE EXTENSION HOUSING»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).

Remove the case side cover. See CASE SIDE COVER. Disconnect the transaxle wiring harness. Remove the pressure control solenoid (322). (Scheme 238)

Scheme 238

Install the pressure control solenoid (322). (Scheme 238) Connect the transaxle wiring harness. Install the case side cover. See CASE SIDE COVER.

1. On models with 3.4L engine, remove the throttle body air inlet duct. On models with 3.8L engine, remove air cleaner assembly. On all models, remove the shift cable lever from the manual shaft. See «SHIFT CABLE»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).
2. Depress the reverse servo cover. (Scheme 239) Remove the snap ring. (Scheme 240) Pull the O-ring seal out through the slot in the case. Use side cutting pliers in order to cut the servo cover O-ring seal.
3. Depress the reverse servo cover, grasp one end of the cut seal and pull the seal out of the servo cover.
4. Remove the reverse servo cover. Remove the servo assembly. Remove the servo spring.

Scheme 239

Scheme 240

1. Jack up the driver side (channel plate side) of the car until it is higher than the differential side. This ensures that the reverse band is in the proper location and not cocked to the channel plate side of the case.
2. Install the servo spring. (Scheme 240) Install the servo assembly. Install the reverse servo cover with new O-ring seal. (Scheme 239) Install the snap ring.
3. Install the shift cable lever to the manual shaft. See «RANGE SELECTOR CABLE»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). On models with 3.4L engine, install the throttle body air inlet duct. On models with 3.8L engine, install air cleaner assembly.

1. On models with 3.4L engine, remove the throttle body air inlet duct. On models with 3.8L engine, remove air cleaner assembly. On all models, remove the shift cable from the wiring harness clip or strap. Remove the shift cable from the Park/Neutral position switch. (Scheme 241)
2. Remove the shift cable from the shift cable bracket. (Scheme 242) If equipped with floor console shift control. Remove the front floor console. See appropriate SHIFT INTERLOCK SYSTEMS article.
3. Pull the carpet back to expose the shift cable. Remove the shift cable from retaining clip(s) or retainer(s) in the passenger compartment.
4. Remove the shift cable retainer from the console shift control. Remove the shift cable from the console shift control.
5. If equipped with a steering column shift control, remove the steering column trim covers. See appropriate SHIFT INTERLOCK SYSTEMS article. Remove the shift cable from the shift control lever. (Scheme 243) Remove the shift cable through the hole in the dash. (Scheme 244)

Scheme 241

Scheme 242

Scheme 243

Scheme 244

1. Install the shift cable through the hole in the dash. (Scheme 244) If equipped with a floor console shift control, see appropriate SHIFT INTERLOCK SYSTEMS article. Install the shift cable through the console shift control bracket. Install the shift cable to the console shift control.
2. Install the shift cable retainer to the console shift control. Install the shift cable to retaining clip(s) or retainer(s) in the passenger compartment. Install the carpet into position. Install the front floor console. See appropriate SHIFT INTERLOCK SYSTEMS article.
3. If equipped with a steering column shift control. Install the shift cable to the shift control lever. (Scheme 243) Install the steering column filler panel. See appropriate SHIFT INTERLOCK SYSTEMS article. Properly route and position the shift cable. (Scheme 245) Install the shift cable to the shift cable bracket. (Scheme 242) Install the shift cable to the Park/Neutral position switch. (Scheme 241)
4. Place the transaxle in the Neutral position. Place the shift control in the Neutral position. Connect each cable section to the following before connecting the 2 cable sections.
5. Insert the metal end fitting of the shift control cable into the transaxle cable end. (Scheme 246) Use the molded end fittings to push the metal end fitting of the shift control cable and the transaxle cable end together until the metal post snaps into place.
6. Depress the adjuster clip once. This mobilizes the adjuster housing toward the transaxle end fitting. Line up the end fittings so they slide together until you feel the parts cam together and lock. Depress the adjuster clip completely. This locks the cable into its adjusted service position.
7. Pull the conduit in the opposite direction to assure full system adjustment of the shift cable. The horseshoe clip with the tab is flush when fully engaged. Ensure the conduit is fully engaged.
8. The horseshoe clip with the tab is not flush when not fully engaged. Install the shift cable retainer and the wiring harness clip or the wiring harness strap. Adjust the shift cable. On models with 3.4L engine, install the throttle body air inlet duct. On models with 3.8L engine, install air cleaner assembly.

Scheme 245

Scheme 246

1. Remove the case side cover. See «CASE SIDE COVER»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Disconnect and reposition the electrical connectors from the following: 2-3 Shift solenoid valve assembly. Fluid pressure manual valve position switch assembly. (Scheme 220)
2. Remove the oil pump bolts (206 and 207). Remove the oil pump from the valve body. (Scheme 248)
3. Disconnect the torque converter clutch pulse width modulation (TCC PWM) solenoid electrical connector. See Remove the TCC PWM solenoid retaining clip (314F). (Scheme 249) Remove the TCC PWM solenoid (334).

Scheme 247

Scheme 248

Scheme 249

1. Install the TCC PWM solenoid (334). (Scheme 249) Install the TCC PWM solenoid retaining clip (314F). Connect the TCC PWM solenoid electrical connector.
2. Install the oil pump to the valve body. (Scheme 248) Install the oil pump bolts (206 and 207). (Scheme 247) Tighten the bolts (207) to 106 INCH lbs. (12 N.m).
3. Tighten the bolts (206) to 12 ft. lbs. (16 N.m). Reposition and connect the electrical connectors to the following: Fluid pressure manual valve position switch assembly. (Scheme 220) 2-3 Shift solenoid valve assembly.
4. Install the case side cover. See «CASE SIDE COVER»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).

1. Remove the case side cover. See «CASE SIDE COVER»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing). Disconnect the transaxle wiring harness.
2. Remove the control valve body bolts (375, 379 and 381) that mount the fluid pressure manual valve position switch to the control valve body (300). (Scheme 250)
3. Carefully remove the fluid pressure manual valve position switch (395). Inspect the fluid pressure manual valve position switch (395) for the following conditions: Damaged electrical connector terminals. Damaged seals. Damaged switch membranes. Debris on the switch membranes.

Scheme 250

Note. When installing the TFP switch handle the switch carefully, the fluid pressure manual valve position switch is very delicate.

1. Carefully install the fluid pressure manual valve position switch (395). (Scheme 250) Install the control valve body bolts (375, 379 and 381) that mount the fluid pressure manual valve position switch to the control valve body (300).
2. Tighten the control valve body bolt (375) to 106 INCH lbs. (12 N.m). Tighten the control valve body bolt (379) to 97 INCH lbs. (11 N.m).
3. Tighten the control valve body bolt (381) to 70 INCH lbs. (8 N.m). Connect the transaxle wiring harness. Install the case side cover. See «CASE SIDE COVER»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).

1. Remove the oil pan. See «DRAINING & REFILLING»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__draining-refilling) under LUBRICATION.
2. Remove the thermo element pins and washers (120 and 123). (Scheme 251)
3. Remove the thermo element (121) and the thermo element plate (122).

Scheme 251

1. Use the Thermo Element Height Gage (J-34094-A) to set the middle thermo pin (123). (Scheme 252) Install the new thermo element plate (122). Install the pin and washer (120).
2. Use the thermo element height gage to set the height of the pin and washer (120) furthest from the accumulator. Use the thermo element height gage to set the height of the second pin and washer (120).
3. Carefully install the thermo element (121) between the 2 pin and washers (120). The "V" in the thermo element (121) must contact the thermo element plate (122). Install the oil pan. See «DRAINING & REFILLING»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__draining-refilling) under LUBRICATION. Fill transaxle with appropriate fluid to proper level. See «LUBRICATION»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing).

Scheme 252

Raise and support the vehicle. Remove the right front wheel. Remove the transaxle brace bolts. (Scheme 253) Remove the transaxle brace.

Scheme 253

Install the transaxle brace. Hand start the bolts to the engine and to the transaxle. Install the transaxle brace bolts to the transaxle. (Scheme 253) Tighten the transaxle brace bolts to the transaxle to specification. See TORQUE SPECIFICATIONS. Install the transaxle brace bolts to the engine. Tighten the transaxle brace bolts to the engine to specification. Install the right front wheel. Lower the vehicle. Connect the negative battery cable.

1. Raise and support the vehicle. Remove the left front tire and wheel.
2. Remove the left inner splash shield. Position a transaxle jack under the transaxle.
3. Slightly take the weight off mount, and remove the transaxle bracket to transaxle mount upper nuts. (Scheme 254)
4. Remove the transaxle bracket-to-transaxle bolts. (Scheme 255) Remove the transaxle bracket.

Scheme 254

Scheme 255

1. Position the transaxle mount to the frame. Hand start the transaxle mount bracket to transaxle bolts. Install the transaxle bracket bolts. (Scheme 255) Start with the forward lower bolt and work clockwise to tighten the transaxle bracket bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__torque-specifications).
2. Remove the support from the transaxle. Install the transaxle bracket to the transaxle mount upper nuts. (Scheme 254) Tighten the transaxle mount upper nuts to specification. See «TORQUE SPECIFICATIONS»(/buick/century/vi-1997-2005/remont/automatic-trans/#automatic-transaxle-servicing__torque-specifications).
3. Install the left engine splash shield. Install the left front tire and wheel. Lower the vehicle.

On models with 3.4L engine, remove the throttle body air inlet duct. On models with 3.8L engine, remove air cleaner assembly. On all models, remove the transaxle vent (press fit) (37) from the transaxle case. (Scheme 256)

Scheme 256

Install the transaxle vent (press fit) (37) to the transaxle case. (Scheme 256) On models with 3.4L engine, install the throttle body air inlet duct. On models with 3.8L engine, install air cleaner assembly.

Raise and support the vehicle. Remove the right front wheel. Remove the vehicle speed sensor wiring harness connector. Remove the vehicle speed sensor bolt (9). (Scheme 257) Remove the vehicle speed sensor (10) from the extension case. Remove the O-ring (11) from the vehicle speed sensor (10). (Scheme 258)

Scheme 257

Scheme 258

Install the O-ring (11) to the vehicle speed sensor (10). (Scheme 258) Install the vehicle speed sensor (10) to the extension case. Install the vehicle speed sensor bolt (9). (Scheme 257) Tighten the vehicle speed sensor bolt (9) to specification. See TORQUE SPECIFICATIONS. Install the vehicle speed sensor wiring harness connector. Install the right front wheel. Lower the vehicle.

Remove the case side cover. See CASE SIDE COVER. Use a small flat-blade tool in order to remove the wiring harness from the solenoid valve(s), TFP manual valve position switch and/or the temperature sensor. (Scheme 220) Remove the wiring harness. Remove the clips retaining the solenoid(s).

Connect the wiring harness. (Scheme 220) Install the wiring harness to the solenoid valve(s), TFP manual valve position switch and/or the temperature sensor. Install the case side cover. See CASE SIDE COVER.

Remove the case side cover. See CASE SIDE COVER. Disconnect the transaxle wiring harness. Remove the 1-2 shift solenoid (315A). (Scheme 259)

Scheme 259

Install the 1-2 shift solenoid (315A). (Scheme 259) Connect the transaxle wiring harness. Install the case side cover. See CASE SIDE COVER.

Remove the case side cover. See CASE SIDE COVER. Disconnect the transaxle wiring harness. Remove the 2-3 shift solenoid (315B). (Scheme 260)

Scheme 260

Install the 2-3 shift solenoid (315B). (Scheme 260) Connect the transaxle wiring harness. Install the case side cover. See CASE SIDE COVER.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• OIL COOLER FLUSHING
• DRAINING & REFILLING
• FLUID CAPACITIES
• CHECKING FLUID LEVELS & CONDITION
• TORQUE SPECIFICATIONS
• RECOMMENDED FLUIDS
• ADJUSTMENTS
• REMOVAL & INSTALLATION
• LUBRICATION