Signs of failing auto tranny

[Loke]

Ive tried searching the forums, but Im unable to find a post listing signs of a failing auto tranny. Since this seems to be *the* major headache for most BMW owners, it would be nice with a post listing signs of failing auto trannies.

I myself have a 1991 525iA M50 with 291.000km, and the auto tranny works very well IMO. The only complain I have, is a rough shift between 2nd and 3rd gear compared to the other gears. I can hardly notice the car shifting gears, but from 2nd to 3rd there is a "yank". (Havent really a good english word for it, since english is not my native language) Did a tranny service nearly 1 year ago when I bought the car, and the old oil was terrible :-( So perhaps its time to do the tranny service again now.

So, experts please pour from your auto tranny knowledge! :-)

[Loke]

No ideas what that little "yank" going from 2nd to 3rd is?

[Javier]

trany is the only one I don't mess around. Yet.

[Tiger]

That sounds like the servo piston is going bad (sticking or leaky seal). The other possibility is valve body internal servo is not operating well just for that particular servo above. My suggestion is to do the fluid & filter change... try using Mobil 1 Tranny Fluid... When doing the fluid flush, you change the fluid 3 times... I know this is a hassle with BMW without dipstick... but that's the only way to dilute old fluids or have a shop use those fancy machine hooked up to your cooler line.

If above doesn't help, then you will have to consider waiting until tranny goes real bad and then get it overhauled or just change it out.

[Loke]

Thanks for replies.

Re Tiger:

I dont really understand what the parts you mentioned are and what they do, just that they are inside the tranny :-P - but are they something you can change without a (complete?) tranny overhaul? And if yes, what does this job involve? ($ estimate)