really loud whine

[Nic01101011]

The transmission emits a loud whine under acceleration in 1,2,3, and 5 gears. It doesn't make noise when cruising or under deceleration, and makes no noise in 4th regardless of driving. I've read that all e30s whine, but my previous one didn't make any noise. The transmission shifts beautifully though. Any ideas?

[HST]

Low fluid? No noise in 4th is weird though.

[Nic01101011]

I have 2 quarts of Redline MTL on the way, and have my fingers crossed that'll fix it, but deep down I have a bad feeling it won't. The shifts are butter smooth..

[Nic01101011]

changed the fluid, noise persists

any more input?

[Toms73NovaSS]

In 4th gear the transmission does not utilize the counter shaft in the transmission, basically it locks the input rotation from the input shaft of the transmission to the output shaft of the transmission, bypassing the counter shaft. So my guess would be either the gear on the input shaft that runs the counter shaft or the bearings that support the input shaft. Either way that is an internal tear down of the transmission.

To quantify my answer: I have not taken a getrag apart just rebuilt borg-warner, however I looked at the schematic of the getrag and it appears that the functioning is the same.