Replacing the Guibo/Flex Disc & CSB - What Else?

[bcrdukes]

Hi guys,

I'm going to be replacing the guibo and CSB for my tranny/driveshaft soon. In addition to this, the tranny mounts and tranny rear main seal.

What else is there? U-joints?

Thanks.

[dashboardmonkey]

if you are replacing the drive shaft you will be replacing the u-joints.

Do your motor mounts as well

[dashboardmonkey]

if you are replacing the drive shaft you will be replacing the u-joints.

Do your motor mounts as well

[jlevie]

Close, the u-joints aren't a field replaceable item. So you'll be replacing the drive shaft with a new or reman unit.

[bcrdukes]

^
Really?

I did a search and it seems like many people have replaced the u-joints either themselves or at a shop. Pelican Parts and BMA also sell the u-joint. The funny thing is BMA lists that you need 3 per car but no mention of such on Pelican. Hmm...

[jlevie]

A BMW drive shaft has the u-joints staked or welded in, which complicates replacement. And after replacing the u-joints the drive shaft needs to be balanced.

[bcrdukes]

So bottom line is pull out the drive shaft and either replace with a new one or remanufactured one, correct?

[jlevie]

Yep!

[JGood]

Does your driveshaft even need replaced? It is possible to have a worn guibo and CSB without having a bad driveshaft. When the guibo fails, the CSB will be right behind, and vice versa.

Get new bolts for the guibo. 6 bolts, 6 nuts. Used ones can work loose if reinstalled.

Don't forget to pre-load the CSB, I think forward 4-6mm IIRC.

And don't forget whatever exhaust hardware/gaskets you'll need when you drop the exhaust to get to the driveshaft. That hardware gets rusty and will probably break/strip.

[bcrdukes]

Thanks JGood.

At this point, I'm only speculating whether or not I need to replace the driveshaft or not. Whenever I'm shifting into gears, primarily 1st, 2nd, and 3rd, I hear a clunk from the rear end of the car from the cabin. I need to further troubleshoot as to what needs to be replaced, but for one, the Guibo, CSB, and transmission rear main seal is definitely on the way out. I was thinking perhaps my drive shaft needs to be replaced in terms of preventative maintenance. After sifting through a few threads using the search, it appears that a u-joint that isn't replaced will wear out the CSB a lot quicker than expected.

Input much appreciated!