1996 6 speed bearing whine

[Doug]

Q: When I bought my car in the spring, with 76,000 miles, the trans was quiet except for a little whine accelerating in 1st gear (probably a rough tooth). Now, @ 81,000 easy driving miles (I DO NOT abuse the car), there is an increasing whine at cruising speed, 3rd,4th,5th and final. Kind of a dry bearing noise, not real loud. Yet. When stopped, clutch in, no noise, but engage the clutch in neutral and the noise becomes audible and increases with RPM. At speed, shifting to neutral or depressing the clutch changes nothing, still have the noise. The unknown here is that my shop, at my request, drained and replaced the lubes in the trans and the differential so we could establish a base line for maintenance and also look for shavings. The noise started after the lube change. So, did they put too thin a lube in the transmission? Or not enough? Am I losing a front carrier bearing or what? Can I drain the gearbox and replace the lube with good old 90wt and an anti-gauling agent and save everything, or am I looking at a teardown? I'm not driving it untill I get this settled.

 

[lone73]

It does sound like possibly they used the wrong lube. Do these guy's have any experience with ZF transmissions? The lube, as you probably know, is not regular 90 weight. Its more like 30 weight. I would ask them what they put into it? Might be on your receipt.
good luck
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[gmjunkie]

It does sound like possibly they used the wrong lube. Do these guy's have any experience with ZF transmissions? The lube, as you probably know, is not regular 90 weight. Its more like 30 weight. I would ask them what they put into it? Might be on your receipt.
good luck
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If they did put 90 wt gear lube in it, It will self destruct over time!!!! 90 wt is to thick to get into the places it needs to to lubricate it!!

 

[LT4man]

Go to this website: http://zfdoc.com

Read everything the Doc says about lube in a ZF trans!

I use the Castrol 10W60 which is only available from a BMW dealer. This oil is specifically formulated for the BMW "M" series engines.

Just happens to work GREAT in a ZF trans!

When you are putting the fluid in the differential, use two (2) bottles of the friction modifier for the clutch plates. You won't have any problems for 100,000 miles.

SAVE THE

 

[Doug]

'96 transmission bearing whine followup question:

Your answers are all pretty consistant, and I also went to the ZFdoc site. Great suggestion, thanks. If I drain the gearbox, save the lube that comes out (for negotiation purposes), replace it with BMW synthetic 10/60, can I save the bearing, or am I looking at a teardown and rebuild? The whine is not pronounced at this point, and I'm not driving the beast.
Of course, the next question is if the lube I take out is the correct stuff ( I guess it will look and feel thin and won't stink like 90 wt.), what do you suppose caused the failure.. maybe a clutch issue?

 

[LT4man]

You are very welcome. Very happy to help you out.

Some pertinent info:

Factory fill for the 96 ZF trans was Kendall 5W30 petroleum oil.

Gordon Killebrew told me any 10W30 synthetic oil could be used. When I took delivery of my 96, I changed the trans fluid using Castrol 10W30 synthetic oil. I had absolutely no gear rattle at idle in neutral.

I did no changes from 1996 until about two years ago. With 85,000 miles, I went to the BMW Castrol 10W60. I could not believe how buttery my shifter felt after the change.

The oil you drain should be very thin and not smell like differential fluid. Sounds to me (no pun intended) like your trans will be fine. I would go ahead and change the fluid and see how it drives.

SAVE THE