George Davis
08-02-2004, 11:28 AM
This picture might be interesting, or maybe unpleasant, if you have a 4L30E automatic transmission. Drove the car (1994 525i) one day, no problems. Next morning, first shift into 3rd, the transmission made a groaning/slipping noise, which it did every shift into 3rd after that, and sometimes when shifting into 2nd. Drove my wife to work, then took the car to an independent auto trans shop that specializes in BMW and Mercedes. The guy told me these transmissions die in 2 ways: either a plastic thrush washer falls apart, allowing things to contact each other that aren't supposed to; or the 3rd gear drum "blows apart". In both cases, the transmission continues to work, but the more it's driven, the more it mulches itself. He said he sees a lot of them that have failed in one of these ways.
In this case it was the 3rd gear drum, the pic shows what he meant by "blows apart". I was lucky, the end of the curl came within 1 mm of getting into a planetary gear set, which would have blown the gear set apart, too. As it was, the box was rebuildable. There is an upgrade metal thrust washer to replace the plastic thing, but no upgrade 3rd gear drums, unfortunately.
Turned out to be a junkyard transmission, so no idea how many miles were actually on it. The car had just under 100,000 miles when I bought it, so the original tranny failed either at or before those miles.
Suggestion: if your 4L30E suddenly starts groaning/slipping in 3rd, stop driving now and get it fixed before it rips itself apart further.
In this case it was the 3rd gear drum, the pic shows what he meant by "blows apart". I was lucky, the end of the curl came within 1 mm of getting into a planetary gear set, which would have blown the gear set apart, too. As it was, the box was rebuildable. There is an upgrade metal thrust washer to replace the plastic thing, but no upgrade 3rd gear drums, unfortunately.
Turned out to be a junkyard transmission, so no idea how many miles were actually on it. The car had just under 100,000 miles when I bought it, so the original tranny failed either at or before those miles.
Suggestion: if your 4L30E suddenly starts groaning/slipping in 3rd, stop driving now and get it fixed before it rips itself apart further.