Automatic Transmission Servicing (4L60-E): Maintenance GMC Savana H2500

SERVICE INTERVALS

Check transmission fluid level at each engine oil change. At 50,000 miles, change the automatic transmission fluid and the filter if the vehicle's GVWR exceeds 8600 lbs. or if the vehicle is mainly driven under heavy city traffic where the outside temperature regularly reaches 90°F (32°C) or higher, in hilly or mountainous terrain, when frequently towing a trailer or used as a taxi, police or delivery service vehicle. If the vehicle is not used under any of these conditions, change the fluid and filter at 100,000 miles.

Checking Fluid Level

1. Start the engine and operate the vehicle for 15 minutes or until the transmission fluid reaches an operating temperature of 180-200°F (82-93°C).
2. Park the vehicle on a level surface.
3. With your foot on the brake, move the shift lever through each gear range. Pause for about 3 seconds in each range, ending in Park.
4. Apply the parking brake and let the engine idle for 3 minutes.
5. Remove the transmission fluid level indicator. Wipe the indicator clean. Insert the indicator. Give the indicator a full twist in order to close.
6. Wait 3 seconds and remove the indicator.
7. Read both sides of the indicator. The fluid must be within the hot cross-hatched area using the lowest level reading.

Checking Fluid Condition

1. Check the fluid color. Is the fluid Red in color? If so, go to step 5 . If not, go to next step.
2. Is the fluid a non-transparent Pink in color? If so, go to step 14 . If not, go to next step. NOTE: Fluid may turn a Dark Brown in color from normal use. This does not always indicate an oxidation or a contamination issue.
3. Is the fluid a Light Brown in color? If so, go to step 5 . If not, go to next step.
4. Is the fluid Black in color and or have a burnt smell? If so, go to step 14 . If not, go to next step.
5. Does the fluid appear as a solid liquid and not foamy or full of bubbles on level indicator? If so, go to next step. If not, go to step 7 .
6. Check the fluid level. Proper level should be in middle of the "X" pattern, on level indicator. Is the level okay? If so, go to step 19 . If not, go to next step.
7. Is the fluid level high on indicator? If so, go to step 12 . If not, go to next step.
8. Is the fluid level low on indicator? If so, go to next step. If not, go to step 4 .
9. Check for any external leak or leaks. Did you find an external leak or leaks? If so, go to next step. If not, go to step 11 .
10. Correct leak or leaks as needed. Are any leak or leaks still present? If so, go to step 9 . If not, go to next step.
11. Add fluid until level is in middle of "X" pattern on the level indicator. Is the level okay? If so, go to step 19 . If not, go to step 6 .
12. Drain fluid until level is in middle of "X" pattern on the level indicator. Is level okay? If so, go to step 19 . If not, go to step 6 .
13. Replace oil cooler and flush lines. See «AUXILIARY OIL COOLER»(ref-154976-S36528377732003060300000) under REMOVAL & INSTALLATION. Is the replacement complete? If so, go to step 15 . NOTE: A small amount of friction material in pan bottom is a normal condition, but large pieces and or metal particles will require complete transmission overhaul.
14. Drain fluid and remove oil pan to inspect. Is there sign or signs of internal component damage noted in bottom of transmission oil pan? If so, go to step 16 . If not go to step 13 .
15. Replace the filter and fluid. See «DRAINING & REFILLING»(ref-154976-S19254344532003060300000) . Is the replacement complete? If so, go to step 6 .
16. Flush oil cooler and lines and check flow. See «OIL COOLER FLUSHING & FLOW CHECK»(ref-154976-S38589303692003071000000) . Is the oil cooler flushing and flow test complete? If so, go to step 17 .
17. Overhaul transmission. See appropriate OVERHAUL article. Is the overhaul procedure complete? If so, go to next step.
18. Add new fluid. Is the procedure complete? If so, go to step 6 .
19. Check the fluid level and correct as necessary. Is the fluid level satisfactory? If so, system is okay. If not, go to step 1 .

RECOMMENDED FLUIDS

Manufacturer recommends Dexron(R)-III ATF.

DRAINING & REFILLING

Note. Transmission may be equipped with a reusable oil pan gasket. Reusable oil pan gaskets are constructed of rubber with metal or plastic backing. On transmissions equipped with a reusable gasket, sealing surface of oil pan is flat. Transmissions not equipped with reusable-type gasket have a ridge on sealing surface of oil pan, and must have a new gasket every time pan is removed. Clean reusable gasket with solvent. Inspect reusable gasket for damage and replace as necessary. Using any other type of gasket in place of reusable gasket may result in fluid leaks.

1. Raise and support the vehicle. Place a drain pan under the transmission oil pan. Remove the oil pan drain plug, if equipped. If necessary, remove the bolts and position aside the range selector cable bracket for clearance while lowering the pan. It is not necessary to remove the cable from the lever or bracket.
2. Remove the oil pan bolts from the front and sides of the pan only. Loosen the rear oil pan bolts approximately 4 turns. Lightly tap the oil pan with a rubber mallet in order to loosen the pan to allow the fluid to drain.
3. Remove the remaining oil pan bolts. Remove the oil pan and the gasket. Grasp firmly while pulling down with a twisting motion in order to remove the filter. Remove the filter seal. (Scheme 137) The filter seal may be stuck in the pump. If necessary, carefully use pliers or another suitable tool to remove the seal. Discard the seal.
4. Inspect the fluid color. Inspect the filter. Pry the metal crimping away from the top of the filter and pull apart. The filter may contain the following evidence for root cause diagnosis: Clutch material. Bronze slivers indicating bushing wear. Steel particles.
5. Clean the transmission case and the oil pan gasket surfaces with solvent, and air dry. You must remove all traces of the old gasket material, unless it equipped with a reusable rubber gasket. Clean rubber gasket with solvent and air dry.
6. To reassemble, coat the new filter seal with automatic transmission fluid. Install the new filter seal into the transmission case. Tap the seal into place using a suitable size socket. Install the new filter into the case. Install the oil pan and a new gasket, if needed.
7. Install the oil pan bolts. Tighten the oil pan to transmission case bolts alternately and evenly to specification. See «TORQUE SPECIFICATIONS»(ref-154976-S18779490572003060300000).
8. If previously removed, install the range selector cable bracket and bolts. Tighten the bolts to specification. See «TORQUE SPECIFICATIONS»(ref-154976-S18779490572003060300000).
9. Apply a small amount of sealant (GM P/N 12346004) to the threads of the oil pan drain plug, if equipped. Install the oil pan drain plug, if equipped. Tighten the oil pan drain plug to specification. See «TORQUE SPECIFICATIONS»(ref-154976-S18779490572003060300000).
10. Lower the vehicle. Fill transmission with appropriate fluid to proper level. See «RECOMMENDED FLUIDS»(ref-154976-S15704054642003060300000) and «FLUID CAPACITIES»(ref-154976-S05037042142003060300000). Check the COLD fluid level reading for initial fill only. Inspect the oil pan gasket for leaks.

Scheme 137

OIL COOLER FLUSHING & FLOW CHECK

Note. Tools required: Transmission Oil Cooler Flusher (J-35944-A), Transmission Oil Cooler Flushing Fluid (J-35944-22), Cooler Flushing Adapter (J-35944-200), measuring cup, funnel, water supply (hot water recommended), water hose with at least 5/8" (16 mm) ID, shop air supply (with water/oil filters, regulator and pressure gage), air chuck (with clip, if available), oil drain container, pail with lid (5 gallon), eye protection and rubber gloves.

Back Flush

1. Inspect the transmission oil cooler pipes for kinks or damage. Repair as necessary.
2. Connect the transmission oil cooler flusher to the oil cooler feed bottom connector. Use the cooler flushing adapter, if required.
3. Clip the discharge hose (5) onto the oil drain container. (Scheme 138)
4. 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 top connector oil cooler return pipe. Use the cooler flushing adapter, if required.
5. Turn the 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. 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.
6. Turn the flusher water supply valve (1) to the OFF position and clip the discharge hose (5) onto an appropriate container with a lid, to avoid splashback. NOTE: Flushing for approximately 2 minutes in each cooler line direction will result in a total of about 8-10 gallons of waste fluid. This mixture of water and flushing fluid is to be captured in an appropriate container for proper disposal.
7. Turn the flusher water supply valve (1) to the ON position and depress the trigger (8) to mix cooler flushing solution into the water flow. Use the clip provided on the handle to hold the trigger (8) down. (Scheme 139) The discharge will foam vigorously when the solution is introduced into the water stream.
8. Flush the oil cooler and pipes with water and solution for 2 minutes. During this flush, attach the shop air supply of 120 psi (825 kPa) to the flushing system feed air valve (2) located on the flusher for 3-5 seconds at the end of every 15-20 second interval to create a surging action.
9. Release the trigger (8) and turn the flusher water supply valve (1) to the OFF position.

Scheme 138

Scheme 139

Forward Flush

1. Disconnect both hoses from the oil cooler pipes and then connect them to the opposite oil cooler pipe. (Scheme 138) This will allow the oil cooler and pipes to be flushed in the normal flow direction.
2. Repeat steps 6 - 8 of the INITIAL FLUSH procedure.
3. Release the trigger (8) of the flusher and allow water only to rinse the oil cooler and pipes for one minute. (Scheme 139)
4. Turn the flusher water supply valve (1) to the OFF position and turn OFF the water supply at the faucet.
5. Attach the shop air supply to the flushing system feed air valve (2) on the flusher, and blow out the water from the oil cooler and pipes. Continue until no water comes out of the discharge hose (5).