BMW 3231 transmisson miracle?

My 1999 BMW 3231 86K miles started making grinding like metal on metal noises BMW dealer and 2 transmission places told me planetary gear was going out and I needed to replace the transmission for $3-4000. After 2 days and a trip on the interstate at 70 and sitting for 2 hrs the noise went away and the gears seem to be working fine. One transmission shop said a gear tooth must have been sheared off and everything went back to “normal”. It is a sealed transmission; but, I have been advised to have the transmission fluid changed now. My question is should I? I have no idea. On one hand it’s sealed and is unsealing and resealing it going to cause more problems. Is there someway you can check and fill the transmission in a sealed unit without actually unsealing it. The bottom line-now that the transmission seems to be OK-Should I or should I not change the transmission fluid? I would appreciate all the advice I can get. Thanks to each of you in advance for responding. Pip

I don’t think your transmission is a “sealed” as you think. The sealed part was really a warning to mechanics from the manufacture not to open them up because the manufacture knows best.

No good can come from servicing a transmission that has internal damage and yours certainly sounds like it does. you need to spend your time finding a replacement transmission that has less of a price tag. I can somewhat understand you working with a Dealer on this but if you search deaper you most certainly will find a non-Dealer option for your problem.

Thanks for your comments. You are the first person I’ve heard from who actually provied a clear explanation addressing the issue. I’ll start looking for a rebuilt transmission. Thanks for your help.


Not necessarily rebuilt. I picked up a transmission for my Volvo at the junk yard for $900 and put it in myself. It had a 90-day warranty. 100k miles later it still works perfectly. Since you don’t know for sure what the noise was, I would hold off on spending the $$ unless you need the car to be extremely reliable.

With regard to servicing your transmission, I don’t think it is sealed, but BMW says that their transmission fluid is permanent. BMW owners tend to agree that this is marketing hype. The transmission works best and lasts longest if you change the fluid every 50k miles or so. I own two with ‘permanent fluid’ and that is what I do. The fluid in the e46s and up is VERY expensive though.

Thanks Hadn’t thought of that. I’ll look into it.