635csi driveshaft noise/vibration

1989 635csi Installed reman driveshaft because of a constant vibration. The u joints were shot and the center support was completely gone. Test drove car and vibration was gone. Returned car to owner, next day owner complained that the car was making a thumping noise under the gear shifter. Test drove car many times and finally made it happen. Only on take off with heavy acceleration there is a knocking noise and vibration, only for a second or so. All other driving conditions no noise or vibration is felt. Removed and sent driveshaft back to reman, they sent a completely different reman driveshaft back. Reinstalled new driveshaft, same problem. Changed rear diff mount and engine and trans mounts, same problem. Going a little crazy here, please offer some suggestions, and don't say it's the rubber flex disc, this car doesn't use one. Thanks again

Broken weld somewhere? Rear subFrame mounts? Rear dogbone links?

hello, ive had a new drive shaft put in only to find out that when installed the balance welds where on oppissite sides of each other. the entire shaft was sent that way from bmw. very simple fix, none the less very aggravative figuring the bull**** out.

Motor mount or trans mount??

When you say drive shaft do you mean prop shaft or as BMW call it carden shaft, When refitting a prop shaft on a BMW you must push the centre bearing assembly foreward to pre load the bearing and then tighten the nuts or bolts which hold it in place, If you do not you will get various vibrations so do this first.

Berta3rd: Have you found the problem yet? I have the same stuation only when taken of in 1st gear but not on 2nd or else even on under hard acceleration. Please advise if possible

Peter Newman, when you say refitting the propeller shaft and pushing the center bearing assembly forward, can you describe this further? I am about to be reinstalling the propeller shaft with a new front universal. I cannot for the life of me figure out how I will succeed as the universal needs to fit over the "centering" pin coming out from the transmission mounting flange. Do I need to move the engine forward, remove the entire drive shaft, or is there something much easier that I am missing?
Thanks,
Chris Lovell

Assemble the front coupling to the gearbox with the bolts slack and then fit the rear coupling again with the bolts slack then raise up and attatch the centre bearing assembly with the two nuts, Then tighten the front and rear couplings and you then need both centre bearing nut slightly loose and push both sides of the bearing mounts foreward two mm and this will pre load the centre bearing and then tighten up both nuts, Simple but VERY important, Have a very good day and happy BMW driving.

Also make sure the bolts on the guibo face the right way, 3 to the front, three to the back

sounds like the hanger bearing. mine did the same rebuilt the entire shaft problem solved. MY shaft actually had a broken spoke on one of the universal joints. Broken but still ran all the way from Florida to NJ. BMW's are amazing when some parts are completely shot, they still run.