Automatic Transmission Servicing (4L80-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 color Red? If so, go to next step. If not, go to step 11 .
2. Is the fluid level satisfactory? If so, system is okay. If not, go to next step.
3. Check the fluid. Is the fluid foamy? If so, go to step 8 . If not, go to next step.
4. Check the fluid level. The proper fluid level should be in the middle of the cross-hatched area. Is the level high? If so, go to step 9 . If not, go to next step.
5. The fluid will be low. Add fluid to the proper fluid level. After repairs, go to next step.
6. Check for external leaks. Were any leaks found? If so, go to next step. If not, go to step 20 .
7. Correct the leak condition. After repairs, go to step 20 .
8. Is the fluid level too high? If so, go to next step. If not, go to step 10 .
9. Remove excess fluid to the proper fluid level. Is the fluid level satisfactory? If so, go to step 20 .
10. Check for contaminants in the fluid. Drain the fluid to determine the source of the contamination. Was the fluid drained? If so, go to step 15 .
11. Is the fluid color non-transparent Pink? If so, go to next step. If not, go to step 13 .
12. Replace the cooler. After repairs, go to step 15 . NOTE: Transmission fluid may turn dark with normal use. This does not always indicate oxidation or contamination.
13. The fluid color should be Light Brown. Is the fluid color Light Brown? If so, go to next step.
14. Drain the fluid to determine if the fluid is contaminated. Was the fluid contaminated? If so, go to next step. If not, go to step 18 .
15. Perform root cause and repair as necessary. See appropriate OVERHAUL article. Is the overhaul complete? If so, go to next step.
16. Using scan tool, press clear TRANS ADAPT function. Are the reset procedures complete? If so, go to next step.
17. Add new fluid. Is the procedure complete? If so, go to step 20 .
18. Change the fluid and the filter. After repairs, go to step 19 .
19. Are the reset procedures complete? If so, go to next step.
20. Is the fluid level satisfactory? If so, system okay. If not, go to step 1 .

RECOMMENDED FLUIDS

Manufacturer recommends Dexron(R)-III ATF.

DRAINING & REFILLING

1. Raise and support the vehicle. Place drain pan under transmission oil pan. Remove oil pan drain plug, if equipped.
2. Remove oil pan bolts and oil pan. Remove the gasket and magnet. (Scheme 264) Remove oil filter. After proper removal of oil filter, remove filter neck seal.
3. Transmission oil pan gasket is reusable. Inspect gasket and replace as needed. Clean transmission case and oil pan gasket surfaces with solvent.
4. To reassemble, install filter neck seal and oil filter. Install oil pan gasket to the pan. Install magnet into the bottom of the pan.
5. Install oil pan to transmission with 17 bolts. Tighten oil pan to specification. See «TORQUE SPECIFICATIONS»(ref-156344-S10541896052003071400000).
6. Apply small amount of sealant (GM P/N 12346004) to drain plug threads, if equipped.
7. Install the oil pan drain plug, if equipped. Tighten drain plug to specification. See «TORQUE SPECIFICATIONS»(ref-156344-S10541896052003071400000).
8. Lower the vehicle. Fill transmission with appropriate fluid to proper level. See «RECOMMENDED FLUIDS»(ref-156344-S36195301832003071400000) and «FLUID CAPACITIES»(ref-156344-S00062355512003071400000). Check the COLD fluid level reading for initial fill only. Inspect the oil pan gasket for leaks.

Scheme 264

OIL COOLER FLUSHING & FLOW CHECK

Note. Do not use solutions that contain alcohol or glycol. Use of solutions that contain alcohol or glycol may damage flushing equipment, oil cooler components and/or transmission components.

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 265)
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 266) 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 265

Scheme 266

Forward Flush

1. Disconnect both hoses from the oil cooler pipes and then connect them to the opposite oil cooler pipe. (Scheme 265) 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 266)
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).