How to Change the Transmission Fluid on a 1989 BMW 325i

1. Start the BMW’s engine and allow it to reach operating temperature, which is displayed about halfway up the temperature gauge. Shut the engine off.
2. Raise the front of the BMW with a floor jack and position jack stands under its subframe. Lower the vehicle onto the jack stands.
3. Crawl beneath the vehicle until you reach the transmission oil pan -- the metal pan on the bottom of the transmission. Place a drain pan directly under the transmission oil pan. Loosen the transmission oil pan drain plug with a ratchet and socket, then remove it by hand. Allow all of the oil to drain from the transmission drain hole.
4. Remove all of the transmission oil pan bolts with a ratchet and socket. Lightly tap the side of the transmission pan with a rubber mallet to break its seal to the transmission. Pull the pan downward and off the transmission.
5. Unfasten the bolts securing the transmission oil screen -- the filter-like component -- with a ratchet and socket, then pull the screen from the transmission.
6. Press a new transmission screen onto the transmission’s valve body and hand-thread its retaining bolts. Tighten the screen-retaining bolts to 4 foot-pounds with a torque wrench and socket.
7. Pull the circular magnet from the bottom of the transmission pan and wipe the debris and light metal shavings off with a clean, lint-free cloth.
8. Pull the old gasket off the gasket-mating surface on the transmission pan and scrape the mating surface with a plastic gasket scraper. Remove all of the sludge and debris out of the transmission pan with clean, lint-free cloths. Set the circular magnet back in it recessed seat in the pan.
9. Apply a thin bead of RTV silicone to the gasket-mating surface on the transmission pan and set a new transmission pan gasket on the gasket-mating surface, lining up the bolt holes in the gasket with those in the transmission pan.
10. Scrape the gasket-mating surface on the bottom of the transmission with a plastic gasket scraper and wipe it off with a clean, lint-free cloth. Set the transmission pan on the underside of the transmission and hand-thread its retaining bolts. Tighten the transmission oil pan bolts, in a crisscross pattern, to 6 foot-pounds with a torque wrench and socket. Hand-thread the transmission oil pan drain plug into the transmission oil pan, then tighten it to 12 foot-pounds with a torque wrench and socket.
11. Find the transmission filler plug on the driver’s side of the transmission. Remove this plug with a ratchet and socket.
12. Insert a flexible-neck funnel into the filler hole and add Dexron-II transmission fluid until the fluid level reaches the bottom of the filler hole, which indicates about 1 ½ quarts. Hand-thread the fill plug into the transmission, then tighten it with a ratchet and socket.
13. Raise the BMW off the jack stands with a floor jack and remove the jack stands. Lower the front of the BMW to the ground.
14. Drive the 325i until it reaches operating temperature, which is displayed roughly halfway up the temperature gauge.
15. Raise the front of the BMW off the ground with a floor jack and slide jack stands under its frame rails. Repeat Steps 11 and 13 to complete the refilling process.
16. Insert a funnel into an empty Dexron-II bottle and fill the bottle with old transmission fluid from the drain pan. Remove the funnel and tighten the cap onto the bottle. Repeat this step until you transfer all of the old fluid into the empty bottles.
17. Take the bottles of old transmission fluid to a local used automotive fluid-recycling center for disposal. Some auto parts stores take old fluid free of charge.