Automatic transmission fluid level check
1. The automatic transmission fluid level should be carefully maintained. Low fluid level can lead to slipping or loss of drive, while overfilling can cause foaming. Either condition can damage the transmission.
Note: Incorrect fluid level readings will result if the vehicle has just been driven at high speeds for an extended period, in hot weather in city traffic, or if it has been pulling a trailer. If any of these conditions apply, wait until the fluid has cooled (about 30 minutes).
6-speed (6L80/6L90) models
2. With the parking brake set, start the engine, then move the shift lever through all the gear ranges, ending in Park. The fluid level must be checked with the vehicle level and the engine running at idle.
3. Press the Trip/Fuel button or the trip odometer reset button to display the transmission fluid temperature on the speedometer or on the Driver Information Center (DIC). If the fluid temperature is between 80 and 90-degrees F, you’ll be using the COLD markings on the dipstick. If it’s between 160 and 200-degrees F, you’ll be using the HOT markings on the dipstick. If it’s above 200-degrees F, wait until the fluid has cooled back down and falls into the «hot» temperature range. If it’s between 90 and 160-degrees F, operate the vehicle until warms up to the «hot» range.
4. With the transmission at the proper temperature, remove the dipstick from the filler tube. The dipstick is located at the rear of the engine compartment on the passenger’s side (see illustration).
7.4 The automatic transmission dipstick is located at the right rear of the engine compartment — flip up the handle before pulling out the dipstick
5. Wipe the fluid from the dipstick with a clean rag and push it back into the filler tube until the cap seats.
6. Pull the dipstick out again and note the fluid level.
7. If the fluid is cold or slightly warm (80 to 90-degrees F), the level should be in the COLD range on the dipstick (see illustration). If it’s hot (160 to 200-degrees F), the level should be in the crosshatched HOT range. If additional fluid is required, add it into the dipstick tube using a funnel. Add the fluid a little at a time and keep checking the level until it’s correct. It is important to not overfill the transmission.
7.7 The automatic transmission fluid must be kept in the regions marked, depending on the fluid temperature
8. The condition of the fluid should also be checked along with the level. If the fluid at the end of the dipstick is a dark reddish-brown color, or if it smells burned, it should be changed. If you are in doubt about the condition of the fluid, purchase some new fluid and compare the two for color and smell.
8-speed (8L90) model
Warning: Never get underneath the vehicle when it is supported only by a jack. The jack provided with your vehicle is designed solely for raising the vehicle to remove and install a wheel. Always use jack stands to support the vehicle when it becomes necessary to place your body underneath the vehicle.
Note: The vehicle must be level to accurately check the automatic transmission fluid, so it will be necessary to raise both the front and rear of the vehicle.
Warning: These transmissions do not have a dipstick to check fluid level. The fluid level is checked at the transmission fluid check plug at the bottom of the transmission pan. To accurately check the fluid level, the engine must be running in Park and the vehicle has to be raised off the ground. There is a risk of personal injury from hot transmission fluid and also from the nearby exhaust system. Therefore if attempting this procedure, wear heatproof gloves and position yourself beneath the vehicle so you are not at risk of being splashed by any transmission fluid. Do not remove the check plug unless the engine is running at idle and in Park, as the transmission fluid drains from the torque converter once the engine is switched off and flows back to the transmission pan. If removed with the engine Off, a large amount of transmission fluid will be expelled from the plug hole.
9. With the parking brake set, start the engine, then move the shift lever through all the gear ranges, ending in Park. The fluid level must be checked with the vehicle level and the engine running at idle. The automatic transmission must be at the proper temperature to obtain an accurate fluid level reading.
10. Press the Trip/Fuel button or the trip odometer reset button to display the transmission fluid temperature on the speedometer or on the Driver Information Center (DIC). The transmission fluid temperature should be between 95 and 113-degrees F.
11. Raise the vehicle and support it securely on jack stands.
Warning: Position your body far enough away from the filler plug hole or oil level check plug hole as hot transmission fluid can cause burns. Also take care as the exhaust is positioned close to the filler plug.
12. Make sure the engine is idling in Park. Place a drain pan under the transmission fluid level check plug, then remove the check plug from the transmission fluid pan (see illustration).
7.12 Locate the automatic transmission fluid level check plug and remove it typical check plug shown
13. Allow the fluid to drain until it starts to just drip from the hole. If no fluid comes out when the check plug is removed, fluid will have to be added until it begins to drip from the hole.
Adding fluid
14. Clean around the top of the fill plug to prevent anything from falling into the transmission.
Note: The fill plug is located on the right side of the transmission case.
15. Use a pair of long needle-nose pliers with a 90-degree bend to unlock the fill plug (see illustration).
7.15 Use angled needle-nose pliers to lift the plunger on the top of the fill plug to unlock the plug
16. With the plug unlocked, use the pliers to lift the plug out of the hole.
17. Add fluid through the fill plug hole using a hand pump with a long hose (see illustration) until fluid starts running out of the fluid level check plug hole.
7.17 Use a hand pump with a long hose to fill the transmission through the fill plug hole
18. Install the check plug into the transmission pan and tighten it temporarily.
19. Install the fill plug and depress the plunger to lock it in place.
20. Check the fluid level (see Steps 12 and 13).
21. Install the check plug and tighten it too the torque listed in this Chapter’s Specifications.
22. The condition of the fluid should also be checked along with the level. If the fluid is a dark reddish-brown color, or if the fluid has a burned smell, the fluid should be changed. If you’re in doubt about the condition of the fluid, purchase some new fluid and compare the two for color and smell.