142 Section 1 Introduction to Automotive Technology Copyright Goodheart-Willcox Co., Inc. This can cause rapid part wear and premature trans- mission failure. To check the fluid in an automatic transmission or transaxle, warm up the engine and move the gear selector through all positions. Apply the parking brake. Place the transmission in park and block the wheels. With the engine still running, locate the transmission dipstick. See Figure 9-7. Tech Tip Don’t “go crazy” looking for the transmission dipstick on some new cars and trucks. You may not find one. Some transmissions and transaxles are sealed at the factory. They are designed to not require fluid changes and periodic checking of fluid level. Some manufacturers provide screw plugs on the side of the transmission case for checking and adding transmission fluid. The procedure is similar to that for a manual transmission. Pull out the dipstick. Wipe it off and reinsert it into the tube. Remove the dipstick again and hold it over a shop rag. The fluid should read between the ADD and FULL marks. Also, inspect the fluid for discoloration and odor. If it smells burned or looks dirty, the fluid should be changed. It is very easy to overfill an automatic trans- mission. Seldom do you have to add a full quart. Normally, if the dipstick reads ADD, only a fraction of a quart is needed to fill the transmission. Sometimes, instructions are written on the dipstick. If in doubt, check a shop or owner’s manual. Service Procedure To change the fluid and filter in an automatic trans- mission or transaxle: 1. Warm the engine and transmission or trans- axle to full operating temperature so the fluid will drain more fully. 2. Raise the vehicle on a lift or secure it on jack stands. If the transmission pan has a drain plug, remove it and allow the old fluid to drain into your catch pan. If the pan does not have a drain plug, remove the pan as outlined in steps 3-10. 3. Remove all but one of the bolts securing the trans- mission pan, Figure 9-8. Be careful not to spill the hot transmission fluid. It can cause painful burns! 4. Loosen but do not remove the last pan bolt while holding the pan in place with a shop rag. 5. Allow the pan to drop and let the fluid pour into a catch pan. 6. Unscrew the last pan bolt and remove the pan. If needed, replace or clean the transmission filter, Figure 9-9. 7. Scrape the old gasket off the transmission pan and housing. 8. Position the new pan gasket using an ap- proved sealer. Use the sealer sparingly. You do not want any to squeeze out of the gasket and into the transmission or transaxle housing. 9. Start all the pan bolts with your fingers. 10. Tighten the pan bolts in a crisscross pattern to their recommended torque specification. Overtightening can split the gasket or distort the transmission pan. 11. If recommended, drain the torque converter (fluid coupling in front of the transmission). A drain plug may be located in the converter. It is usually under a rock shield on the front of the transmission housing. 12. Refill the transmission with the correct type and amount of transmission fluid. If required, check a service manual for details. In most cases, you must pour fresh fluid into the dipstick tube. 13. Start the engine and shift through the gears. 14. Check under the car for leaks and recheck the transmission fluid level. Hot OK Cold OK Hot add Add Saab Figure 9-7. Check automatic transmission fluid level with the engine running and the transmission in park. Compare the fluid level to the marks on the dipstick. If needed, add the correct amount and type of fluid.