Testiment to the 904 Trans

New fluid will not eat up or finish off the clutches, or otherwise kill a transmission that is fundamentally sound. If the transmission is walking-dead, it will die soon with new fluid or old. If it is still basically sound but is being beaten up by varnish and lack of lubricity (old fluid), it will not be basically sound for long. On the other hand, old fluid will contaminate new fluid. For the same reason, we do not change just the oil without changing the filter; four quarts of clean oil plus one quart of dirty oil equals five quarts of dirty oil. Do a complete fluid and filter change, including draining the torque converter, and a proper band and linkage adjustment.

Nice new pans with unwarped rails for the A904 can be had from the dealer under p/n 52118 779AD, and they even include a spiffy magnet to catch metallic shavings. Whether you go with a new pan or not, save yourself a bunch of current and future hassle: Discard the floppy cork or rubber pan gasket that comes with the filter kit. Instead, from the Chrysler dealer get the really nice double-seal, reusable rigid pan gasket P/N 4295 875AC.

Fluid selection: a reputable brand of ATF+4 or Dexron-VI; see here.