Backend Clunking while Shifting (88 528e manual)

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somethin2do
Posts: 21
Joined: Apr 25, 2022 4:06 PM
Location: Arkansas

Backend Clunking while Shifting (88 528e manual)

Post by somethin2do »

Hi All - I have a backend clunk on my 88 528e manual. while switching from 1st to second gear it is more prominent and you can really feel it in the back. I just replaced the rear subframe bushings since they were bad, however this did not solve my issue. I believe it's either the driveshaft, diff mount or suspension?

What do you recommend me starting with?
Planning on:
Rear subframe bushings (just finished this and did not help with the clunking)
Control arm Bushings
Sway bar end links
Cv boot

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Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: Backend Clunking while Shifting (88 528e manual)

Post by Mike W. »

IIRC the diff mount is worst in reverse, but it's quick and easy to check, so I'd pull it and see if it's broken rather than just guess. If it's broken it will be obvious. U joints usually get stiff and vibrate, but it's possible it's so far gone it's loose instead of stiff, but in neutral again it should be obvious with everything unloaded. Could be the diff itself, it could be where the diff is bolted to the subframe.
somethin2do
Posts: 21
Joined: Apr 25, 2022 4:06 PM
Location: Arkansas

Re: Backend Clunking while Shifting (88 528e manual)

Post by somethin2do »

Mike W. wrote: May 17, 2022 5:02 PM IIRC the diff mount is worst in reverse, but it's quick and easy to check, so I'd pull it and see if it's broken rather than just guess. If it's broken it will be obvious. U joints usually get stiff and vibrate, but it's possible it's so far gone it's loose instead of stiff, but in neutral again it should be obvious with everything unloaded. Could be the diff itself, it could be where the diff is bolted to the subframe.
Thanks! Just checked and rear diff mount is pretty worn and torn on the sides but not broken. See pics below

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Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: Backend Clunking while Shifting (88 528e manual)

Post by Mike W. »

No, it's broken, very broken. The 4 bolt flange is supposed to be bonded to the center portion. The pic is what it should look like, adjusted for time. I don't know what brand to suggest, URO has a terrible reputation, BMW OE is $100. Others might be available.

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somethin2do
Posts: 21
Joined: Apr 25, 2022 4:06 PM
Location: Arkansas

Re: Backend Clunking while Shifting (88 528e manual)

Post by somethin2do »

Mike W. wrote: May 17, 2022 6:28 PM No, it's broken, very broken. The 4 bolt flange is supposed to be bonded to the center portion. The pic is what it should look like, adjusted for time. I don't know what brand to suggest, URO has a terrible reputation, BMW OE is $100. Others might be available.

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Ohh got it. Thank you. Hope the fix is this easy then haha. Will order a new one and hope that solves my issues
adam_poll
Posts: 206
Joined: Jul 23, 2014 8:19 PM
Location: Kitchener, Ontario, Canada

Re: Backend Clunking while Shifting (88 528e manual)

Post by adam_poll »

Get that CV joint boot replaced and clean out the joint and pack it well with new grease while you're at it. Hopefully it is still savable but if it's gone to long exposed to a bunch of crap it might be done. The diff mount is the biggest part of your clunk but a worn out CV joint wont help. There are cheap brand new replacements available from Rock auto but you're better off saving the original. If you do replace with something new (don't get "rebuilt") it is worth pulling the boots on the new ones as well and making sure there is lots of grease everywhere it needs to be (pack it into the joint!). I'm running a set of those axles in my car and they have been okay for now but definitely not as good as OE.

If you can handle the diff mount I'm betting you can do the axles/CV joints and boots as well. Make sure to clean out the allen head bolts well and use a good bit on them so you don't round them out (you can get a box of 25 new bolts from McMaster Carr which is a good idea and will cover both sides). A small puller can make getting the axle out of the joint easier, do both boots while you have it out and one of the joints off. I think CEK covered this in either his Maytag or Vlad threads with some good pictures. If the CV joint comes apart while you have it off the axle (which makes it easier to clean and grease) it can go back together two ways but only one will work, when it is done right the joint will have free angular motion as well as in and out, when it is wrong it will be very stiff and not have any in and out motion. Prepare to get covered in grease.
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