The transmission pan gasket on a 1999 Pontiac Sunfire is designed to seal the transmission fluid pan to the transmission housing. Contrary to old-fashioned paper gaskets, this gasket is made from a combination of metal and rubber and designed to be reusable. As time passes, the gasket material can corrode and cause a transmission fluid leak. Since the transmission pan must be removed in order to replace the gasket, its an excellent time to replace the transmission filter that lies beneath the transmission pan. The transmission pan gasket and filter are both available from most auto parts stores.
Instructions
- 1
Turn off the engine and let the vehicle cool down for at least one hour before beginning. Raise the front of the vehicle using a floor jack and lower it down onto jack stands. Make sure the Sunfire is level and secure before continuing.
2Place a drain pan underneath the transmission and loosen the transmission pan bolts using a metric socket and a 3/8-inch ratchet. Hold the transmission pan to the transmission with one hand and remove the bolts with the other hand. Remove the pan from the transmission, taking care not to spill fluid outside of the drain pan.
3Remove the pan gasket from the transmission. Remove the transmission filter and filter seal from the transmission by gently twisting and pulling at the same time. Make sure the transmission filter seal is not still stuck inside the transmission. Occasionally, the filter comes out and the seal remains inside the transmission. If this happens, gently pry the old seal out of the transmission with a small flat-head screwdriver.
4Install the new transmission filter seal onto the transmission filter. Lubricate the filter seal with a small amount of clean transmission fluid. Install the filter into the transmission using a pushing and twisting motion until its fully seated.
5Clean the transmission pan using brake cleaning solvent, a plastic gasket scraper, and clean shop rags. Remove any traces of old gasket material. Clean the transmission housing surface where the pan gasket meets the transmission using the same materials to remove any traces of old gasket material. Place the new gasket on the transmission pan and reinstall the transmission pan. Coat the bolts with a small amount of medium-strength threadlocker. Tighten the bolts hand-tight, then tighten them with a torque wrench in an alternating pattern to 89 inch-pounds.
6Refill the transmission to the appropriate level with Dexron-III automatic transmission fluid. For vehicles equipped with the four-speed transmission, there is no dipstick in the engine compartment. There is a small plug on the outer edge of the passenger-side CV shaft housing. With the vehicle still lifted, remove this plug using a box-end wrench and add 6.9 quarts of transmission fluid using a funnel through the transmission vent cap hole in the engine compartment, on top of the transmission case housing. Six point nine quarts is the manufacturer-specified fluid replacement amount for the pan removal. Once fluid spills out of the CV shaft fill hole, the transmission is full. Replace the fluid plug and lower the vehicle back to the ground.
For vehicles equipped with the three-speed transmission, there is a transmission fluid dipstick in the engine compartment. Lower the vehicle back to the ground, start the engine and leave the transmission in park. Add four quarts of transmission fluid using a funnel through the dipstick tube. Four quarts is the manufacturer-specified fluid replacement amount for the pan removal. Wait one minute for the fluid to drip down the dipstick tube, then replace and remove the dipstick to verify that the level is correct. Add fluid if necessary.
7Close the hood and test drive the vehicle. Return home and check for leaks.
