Okay - Just got back from AAMCO. Good news and not so good news.
Although I still don't think they really understand BMW's at this shop (didn't know this particular Getrag tranny doesn't have a rebuild kit), they do know tranny's. AllData charges 6.5 hours of shop time to remove and reinstall the tranny.
This shop scoped and test drove the car and came to the same conclusion that my mechanic has come with, Oaksenov, and this forum. Whine is coming from the bearings in the transmission. The good news is they did confirm the noise is not diff, driveshaft, or wheel bearing related. Also, they said the clutch was working fine and gear shifts were perfect. Even more good news, they believe it would not be a good idea to have the tranny replaced at this time. The owner says in all his 25 plus years of being in business, he's never seen a bearing explode in a transmission that was properly topped off with spec fluid. He further showed me a couple spare bearings and began to explain that these bearings are put around gears which are so tightly spaced in terms of tolerance, that they could never have the opportunity to explode. He also said that the sound that I am hearing is probably either some pitting in the bearing races or the balls themselves being pitted from metal to metal contact. He said worst case the sound will eventually get so loud that the car can't be driven, not because of the tranmission but only because of the noise it will make. Best case, depending on whether you go with a thicker gear oil, the noise could also be completely eliminated. Truth be told though, he also said he was speculating because he's never had one come in with that condition.
The fact that the OP continues to drive his 5er 3 years since posting this and now 30K miles later, and not noticing any change in tranny behavior good or bad, seems to verify that this statement has merit.
As for the use of oil or metal chemical additives, he didn't seem to encourage or discourage the use of it.
One final question he asked is if I knew of any TSB's or recalls on the transmissions. I said I didn't know and he proceeded to check into it and came up with the following comment,
'MTF-LT2 superseded MTF-LT1. MTF-LT2 is not yet available in the US market. In the interim MTF-LT1 can be used.'
Anyone here know what the oil properties are for LT2. Is it thicker or thinner? I definitely plan to change out my fluid for this one or possibly add an additive to it.
Oaksenov - Any update on the additive, did it quiet down 3rd or 4th gear for you? I actually plan to use this stuff, Lubro Moly MoS2 Anti-Friction For Gears. Looks like it's specifically for transmissions and for reducing friction and/or whine.
- 2008 R350 Mercedes Wagon
- 2003 M3 Coupe - Alpine SMG
Last edited by aa240sx; 10-13-2011 at 12:25 PM.