In Reply to: 89 735iL Tranny Problems? posted by JBachmann on April 08, 2001 at 11:09:05:
These ZF manufactured units were notorious for their burning out the first clutch pack if you revved them too high in idle or park; that left you with reverse only. From what i understand off other internet sites, the units run some ridiculously high oil pressure even at idle, and there is a seal on the input shaft INSIDE the unit that wears, then as you rev in idle can leak into the front clutch pack, turning it on when it shouldn't be. The rebuilds apparently had some pressure relief built in to fix this...
Other than this they are a reasonable unit... just keep being nice to them eg
1) change the oil regularly with filter too
2) clean pan magnets too
3) make sure if it "misbehaves" it's not a simple dirty plug or switch in the electronics controller
4) don't race in idle or park
5) don't let others (eg AC service, emissions tests) do the racing either
I am the guy who is considering the purchase of a 735iL with the 4 speed Auto Tranny. I did an archive search on tranny problems and it seems like the 88's have the most problems. My potential car has 157,000 miles on it and in my test drive showed no obvious problems with it. However, I don't know if I can expect a major tranny repair sometime soon. If the 89's have a history of tranny problems I may decide to avoid this purchase. The car really seems nice though. Thanks in advance for any help or advice.