When adding or refilling the transaxle, DEXRON® III Automatic Transmission Fluid is preferred. DEXRON® IIE is an acceptable substitute. It's a good idea to purchase a quart or two of GM DEXRON® III Automatic Transmission Fluid from an authorized GM dealer so the correct transmission fluid is always available.
- Park the vehicle on a level surface. Apply the parking brake and block the wheels.
- Start the engine and operate the vehicle for 15 minutes or until the transaxle fluid reaches operating temperatures; about 180-200 °F (82-93°C). The end of the dipstick will be too hot to hold comfortably.
- While the engine is idling and with your foot on the brake pedal, move the shift lever through each gear range, ending in Park.
- Locate and pull out the transaxle dipstick, located at the rear of the engine and wipe off the splash fluid.
- Push the dipstick completely in the filler tube, wait three seconds, then pull the dipstick out again.
- Check both sides of the dipstick. Generally, an area of etched lines designed to retain fluid, called the crosshatch area, shows the acceptable range of fluid level. The fluid level is acceptable if it is anywhere within the crosshatch area. The fluid level does not have to be at the top of the crosshatch area. DO NOT add fluid unless the level is below the crosshatch area. The fluid level will be higher on the dipstick when the transaxle is cold; the level will drop at operating temperature.
- The fluid color should be light brown. Transmission fluid may turn dark with normal use. This does not always indicate oxidation or contamination. If the fluid is foamy, the transaxle may be overfilled. If the fluid color is a milky, non-transparent pink, there is likely contamination from the engine's cooling system by way a failed transmission oil cooler in the radiator. Since coolant will adversely affect the seals and friction plates in the transaxle, this requires immediate replacement of the transmission oil cooler (usually a complete radiator replacement) and a complete drain and refill of the transaxle fluid.
- If the fluid level is low, add only enough DEXRON® to bring the level into the crosshatch area. It generally takes less than a pint. Do not overfill an automatic transmission. If the fluid level is too high, it can lead to foaming of the fluid, oil coming out of the vent, and overheating.
DRAIN AND REFILL
- The fluid should be drained when warm so contaminants are in suspension in the transaxle fluid.
- Raise and safely support the vehicle on safety stands.
- Place a suitable drain pan under the transaxle fluid pan.
- There is no drain plug for changing the transaxle fluid, so fluid change on most automatics is messy. Draining the fluid involves loosening some bolts, removing others, and, after the pan is loosened, letting the fluid run out from the joint between the pan and gasket and the transaxle body. Use a drain pan with a large enough opening to accommodate draining the fluid from a large section of the pan.
- There are twenty oil pan bolts. Loosen and remove only the bolts from the front and sides of the pan.
- Loosen the rear bolts about four turns.
- Lightly tap the pan with a rubber mallet to loosen and allow the fluid to drain.
- Remove the remaining bolts, the pan and the gasket. Hold the pan level to keep a small amount of fluid in the bottom. This allows you to check the sediments in the pan for contaminants. Remove the pan and set aside.
- The transaxle oil filter has a small neck that is a press-fit into the transaxle case. It should pull straight out. A little careful prying may be required. The rubber grommet that accepts the neck on the filter will likely remain in the transaxle case. Use a small screwdriver to carefully remove the seal. Use care not to damage the case sealing surface.
- Inside the pan should be a small magnet. Inspect the oil pan magnet for small bits of steel. The factory places the magnet here to trap stray metal particles. Excessive amounts of steel shavings indicate internal transmission damage. A small amount of sediment in the pan is normal as the friction elements wear.
- If desired, use side cutters to open up the transaxle oil filter assembly by cutting or prying the metal crimping away from the top of the filter and by pulling the filter apart. Inspect the filter for excessive amounts of the following: clutch plate assembly fiber material, indicating clutch distress; bronze slivers, indicating bushing wear; steel particles, indicating internal transaxle wear.
- Clean all parts well. Clean all traces of old gasket off of the oil pan gasket rail as well as the sealing surface on the transaxle. Use care not to damage the sealing surface on either area.
- Inspect the oil pan for damage to the sealing surface and dents or cracks in the pan.
- If the oil filter seal came out of the case, install it using a socket as a driver. Gently tap in with a plastic mallet. Using the same plastic mallet, gently tap the filter neck in place.
- The design of the steel-core factory gasket is such that it may be reusable, if not bent or otherwise damaged. Note that most replacement transaxle oil filters come with a new gasket. Lay the oil pan gasket on the pan and install the pan to the case. Normally, no sealer is used. Start a few bolts at the ends of the pan to hold it and to keep the gasket from moving out of position. Install all 20 bolts and tighten to 97 inch lbs. (11 Nm). Do not overtighten or the gasket could be squeezed out of position and/or the bolt threads in the aluminum transaxle case could be damaged.
- Lower the vehicle to the floor.
- To refill the transaxle from just a bottom pan removal, 7.4 quarts of DEXRON® IIE or DEXRON® III will be required. Use a funnel to reach the filler/dipstick tube. Use care not to spill fluid in the engine compartment.
- Check for leaks.