Automatic Transmission Servicing - Except Allison: Other GMC Yukon Denali

Transfer Case

Check transfer case fluid level at each engine oil change. Under normal driving conditions, change transmission fluid every 50,000 miles.

Manufacturer recommends Dexron-III ATF for Borg-Warner 4401, Borg-Warner 4470, NV241C, NV243C, NV261C and NV263C. Manufacturer recommends Auto-Trak II Fluid (GM P/N 12378508) for NV246.

The following capacities given are approximate. Correct fluid level should always be determined by marks on dipstick, rather than amount of fluid added. DO NOT overfill. See TRANSMISSION FLUID CAPACITIES table.

TRANSMISSION FLUID CAPACITIES

The following capacities given are approximate. Correct fluid level should always be determined by level of fluid at fill hole, rather than amount of fluid added. DO NOT overfill. See TRANSFER CASE FLUID CAPACITIES table.

TRANSFER CASE FLUID CAPACITIES

Preparation

1. After the repair or replacement transmission 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 20-21 oz. (0.6L) of flushing solution using the measuring cup (6). DO NOT overfill. Install the fill cap (9) on the flusher and pressurize the flusher tank (4) to 80-100 psi (550-700 kPa), using the shop air supply at the tank air valve (9). (Scheme 178)
3. Connect the flusher discharge hose (5) to the oil cooler return pipe (top connector) (may require J-35944-600). Clip the discharge hose (5) onto the oil drain container. Attach the flusher to the undercarriage of the vehicle with the hook provided, and connect the flushing system feed supply hose (3) from the flusher to the oil cooler feed pipe (bottom connector) (may require J-35944-600). (Scheme 179)
4. With the water supply valve (1) on the flusher in the OFF position, connect the water supply hose (7) from the flusher to the water supply at the faucet. (Scheme 178)and (Scheme 179). Turn ON the water supply at the faucet.

Scheme 178

Scheme 179

TRANSMISSION & OIL COOLER FLOW CHECK

1. Disconnect both hoses from the oil cooler pipes. Connect the oil cooler feed pipe (bottom connector) to the transmission and the return pipe (top connector) (may require J-35944-600) to the discharge hose (5). Clip the discharge hose (5) onto the empty oil drain container. see scheme 8
2. Confirm the transmission is filled with ATF. See «CHECKING FLUID LEVEL»(ref-138423-S36513837592002041300000). Start the engine with the transmission 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. see scheme 8 Start the engine with the transmission in PARK range and run for 30 seconds. A minimum of 2 qts. (1.9L) must be discharged during this 30 second run time. Perform the following according to the flow rate: Insufficient feed flow: Inspect the transmission. 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 transmission and fill with appropriate fluid to proper level. See «RECOMMENDED FLUIDS»(ref-138423-S05263478952002041300000) and «FLUID CAPACITIES»(ref-138423-S24711245332002041300000). Inspect the transmission oil cooler pipe connections at the radiator, the auxiliary cooler (if equipped) and the transmission for leaks.

ON-VEHICLE REPAIRS

Various components may be serviced without transmission removal, depending on application. For servicing of these components, see appropriate component under ADJUSTMENTS and/or REMOVAL & INSTALLATION . For additional information on testing electrical components, see appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.

PARK/NEUTRAL POSITION SWITCH

With an assistant in driver's seat, raise and support vehicle. The transmission must be in the PARK or NEUTRAL positions only. Loosen the PNP switch retaining bolts and rotate the switch slightly, while assistant attempts to start engine. After engine starts, turn engine off. Tighten PNP switch bolts to specification. See TORQUE SPECIFICATIONS . Ensure vehicle does not start in any range other than Park and Neutral.

SHIFT CABLE (EXCEPT ESCALADE)

1. Ensure the gearshift lever and the transmission manual shaft lever are in the Park position. Raise and support the vehicle. Pull back the white plastic cover (1) on the center connector. (Scheme 180)
2. Pull up on the center tabs of the lock button (2). (Scheme 181) NOTE: This step must be performed correctly to avoid a misadjusted cable. Do not grasp the shift cable end (2) during this procedure.
3. Release the shift cable end (2) and allow the blue spring to tension/adjust the shift cable system. (Scheme 182) Pull the White cover (3) on the shift cable end (1) back.
4. Push the Natural colored lock button (2) down to engage the locking teeth on the shift cable end (1). (Scheme 183) Release the White cover (1). (Scheme 184)
5. Verify the White cover (1) conceals the Natural colored lock (2). (Scheme 185) If the White cover (1) does not conceal the Natural colored lock (2), the shift cable must be readjusted.
6. Test the transmission for proper shift operation. If all of the gear positions cannot be achieved, the shift cable must be readjusted.

Scheme 180

Scheme 181

Scheme 182

Scheme 183

Scheme 184

Scheme 185

SHIFT CABLE (ESCALADE)

1. Position the gearshift lever to the PARK position. Apply the parking brake. Raise the vehicle. Position the transmission lever to Park. Rotate the transmission lever clockwise until it reaches the full mechanical stop position.
2. Slide the black retaining clip forward on the transmission lever cable end. This will allow the White lock button to be pushed out. Push the White lock button on the transmission lever cable end out. This will free the metal core adjust body which is inside the cable end. DO NOT push the White lock button completely out. (Scheme 186)
3. Inspect the metal core adjust body on the cable end for dirt or debris that may restrict the travel. Remove any debris by washing the cable end, the metal core adjust body, and the white lock button with soap and water. If the travel of the metal core adjust body remains restricted after the cleaning, replace the cable assembly. See «SHIFT CABLE (ESCALADE)»(ref-138423-S13123367192002041600000) under REMOVAL & INSTALLATION.
4. Lower the vehicle. Ensure the parking brake is applied. Turn the ignition switch to the ON position. Move the gearshift lever from Park to Low gear and back to Park 10 times. Place the gearshift lever in the PARK position.
5. Turn the ignition switch to the OFF position. Raise the vehicle. Position the gearshift lever to the PARK position. Rotate the transmission lever clockwise until it reaches the mechanical stop position. Push in the white lock button in order to secure the core adjuster body inside the transmission lever cable end. (Scheme 187)
6. Slide the Black retainer clip rearward over the cable end until it covers the white lock button. Lock the clip over the cable end. Lower the vehicle. Turn the ignition switch to the ON position. Ensure all the transmission shift light positions ("P", "R", "N", "D", "3", "2"and "1") illuminate while engaged.
7. If you cannot perform this task, repeat the cable adjustment procedures. Ensure the engine starts in Park and in Neutral positions only. If the engine does not start in Park and in Neutral, the PNP switch may need adjustment. See «PARK/NEUTRAL POSITION SWITCH»(ref-138423-S20953779052002041300000).

Scheme 186

Scheme 187

CONTROL & SHIFT SOLENOIDS (4L60-E)

Note. Do not remove the valve body for the following procedures. Removal of the 1-2 accumulator is necessary only if servicing the pressure control solenoid.

CONTROL VALVE BODY (4L80-E)

Note. Tools required: Transmission Assembly Lubricant (J-36850).

EXTENSION HOUSING REAR OIL SEAL (4L60-E)

Note. Tools required: Rear Extension Seal Installer (J-21426).

Note. Tools required: Park/Neutral Position Switch Adjustment Tool (J-41364-A).

REVERSE SERVO (4L80-E)

Note. Tools required: Gauge Pin (J-21370-10), and Band Apply Pin Checking Tool (J-38737).

Checking Procedure

1. Place the Gauge pin in the servo bore. (Scheme 188)
2. Position the apply pin checking tool over the bore with the hex nut facing the parking pawl linkage. Tighten the band apply pin checking tool with the 2 rear servo cover bolts to 18 ft. lbs. (24 N.m). (Scheme 189)
3. Ensure the gauge pin moves freely in the tool and the pin bore.
4. In order to determine the correct pin length, tighten the nut on the gauge to 25 ft. lbs. (34 N.m). Select the correct band apply pin length. (Scheme 190)

Scheme 188

Scheme 189

Scheme 190

Note. The shift cable is a 2 piece shift cable. The front half (column end) or rear half (transmission end) of the shift cable can be removed without removing the other end/half of the shift cable. Perform the part of this procedure that applies to the removal of that half of the shift cable unless both halves are being replaced.

2-4 SERVO (4L60-E)

Note. Tools required: Servo Cover Depressor (J-29714-A), Piston Remover (J-22269-01), and Band Apply Pin Tool (J-33037)