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Discussion Starter #1 (Edited)
So I replaced my driveshaft, guibo, and rear diff pinion seal about 6 weeks ago and all was good until about a week ago when I began hearing a "whining" noise coming from my rear end when in gear and decelerating. I put the car on the lift today to find this <embed type="application/x-shockwave-flash" allowfullscreen="true" allownetworking="all" wmode="transparent" src="http://static.photobucket.com/player.swf" flashvars="file=http%3A%2F%2Fvid134.photobucket.com%2Falbums%2Fq112%2Fbabydocjd%2FIMG_14231_zpsb368a384.mp4&title=" height="361" width="600"> Obviously this should not be happening. Can anyone chime in and give me some advice on how to fix it? :dunno: thanks in advance..
 

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That explains your diff whine. The pinion shaft nut has come loose. I guess it didn't get torqued up and locked properly when the seal was replaced.
 

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Discussion Starter #6
That explains your diff whine. The pinion shaft nut has come loose. I guess it didn't get torqued up and locked properly when the seal was replaced.
Thanks for your reply, so I need to re-tighten the pinion shaft nut and that should solve this issue?
 

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Simple answer is no. Messing with that nut causes all sorts of evil, and only the people that know a few things about differentials can set the nut (pinion bearing tension) where it should be. Chances are if you've been driving around with it loose some pinion bearing damage has occurred.
 

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Discussion Starter #8 (Edited)
Simple answer is no. Messing with that nut causes all sorts of evil, and only the people that know a few things about differentials can set the nut (pinion bearing tension) where it should be. Chances are if you've been driving around with it loose some pinion bearing damage has occurred.
Well I think I can get the correct torque on the pinion nut this time.
 

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The trouble is its not as simple as torquing up the nut. The nut crushes a sleeve to create a certain amount of preload on the two pinion bearings. The crush is set by measuring the turning torque on the pinion shaft as the nut is tightened. When replacing the pinion seal, the nut position on the shaft should have been marked so the nut could be returned exactly to that position. I suggest you get a driveline shop involved.
 

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Discussion Starter #10
The trouble is its not as simple as torquing up the nut. The nut crushes a sleeve to create a certain amount of preload on the two pinion bearings. The crush is set by measuring the turning torque on the pinion shaft as the nut is tightened. When replacing the pinion seal, the nut position on the shaft should have been marked so the nut could be returned exactly to that position. I suggest you get a driveline shop involved.
I did mark the pinion nut and the pinion shaft with a hole punch before the disassembly.i think where I went wrong with the reinstall was by not lining these two marks up when I re-threaded the nut back on. In any case thanks for the help friend :).
 

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Good thing you marked the pinion and nut. Re-torque the nut until your marks align and install a new lock plate (33121205138). If it continue to whine, you may have done damage to the bearings.
 

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Discussion Starter #12
So I wanted to update anyone following this thread as well as give info to all future searchers who may have this issue with their e39 m5. As I said before I previously marked the pinion nut and pinion shaft with a center punch to identify the proper position they need to be in when re-installing them, this is PARAMOUNT. I followed the BMW workshop manual BMW Workshop Manuals > 5 Series E39 M5 (S62) SAL > 1 Service Information > 0 Maintenance And General Data > 1 SI Modified Change Intervals E9x-M3-US to a T besides using a impact wrench to get the final torque needed. :/. So everything's back in place and torqued down properly and the whine is gone as of now and hopefully forever, thanks for the help everyone who's replied to this thread. Happy Motoring!
 

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I'm curious about how much the crush sleeve is compressed when the pinion nut is torqued down. When you snugged up the nut until it just brought the 2 bearings into contact with the crush sleeve, how much farther did it need to be turned to get the punch marks aligned? 1/8 turn, 3/4 turn?
 

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Discussion Starter #14
I'm curious about how much the crush sleeve is compressed when the pinion nut is torqued down. When you snugged up the nut until it just brought the 2 bearings into contact with the crush sleeve, how much farther did it need to be turned to get the punch marks aligned? 1/8 turn, 3/4 turn?
That's a good question. Basically I tightened it 31 turns by hand socket and wrench from 6:00 to 10:00 and at that point the two marks were exactly parallel from each other. Then I used the impact gun to tighten the nut 1/2 turn to get the two marks to meet. You just have to be very gentle with the gun so as not to over-tighten it and crush the sleeve too much. Bdrrup, check it, Bdrrrrup, check it, Bdrrrrup check it, You get the idea.
 
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