[Robertt24]

Hey guys, I just bought a 2001 320ci manual and it clunk's whenever you change gears or go on and off the throttle hard. You can drive the car smoothly and it makes no sound. Today I looked under it and told my brother to brake and release clutch to see if the bushing of the differential were bad however it didn't seem to have any to none movement in it but what I did find out is that the clunking was coming from where the driveshafts connects to the differential I put image below to show.
Any advice what this could be ?

Thanks in advance.

 

[dannyzabolotny]

That’s called a U-joint, and they’re not meant to be replaceable. You can have a driveshaft specialist rebuild the driveshaft to put in new U-joints, buy a remanufactured driveshaft, or buy a good used driveshaft. That all depends on your budget.

 

[dmax]

Csb more likely than driveshaft. Possibly rear diff bushing. If doing csb, replace flex disk too. Mark driveshaft well before splitting.

 

[Inlajnsiksbenzin]

It can be the rear U-joint. Mine did the same. It had a side to side free play. I removed that U-joint and found out it was toast. Best for you would be to source used one that has no play. It will hold for some time if driven normally.

 

[Robertt24]

Thanks for the reply guys.

I’ve found a bargain prop shaft on eBay however it’s only the rear half would I be able to replace that half with the prop shaft that’s on the car now??

 

[russcoop]

I did and lined up the dots an running smooth today

 

[Robertt24]

I did and lined up the dots an running smooth today

Which dots??

 

[russcoop]

all drive shafts have little white dots, one on each section near where they go together, sometimes you got to look for them maybe under some dirt

 

[russcoop]

actually I have swapped out three rear drive shaft sections with no vibrations I also sink the U-joint in used oil to lub it, rust belt takes its toll as the joint is exposed to plash salt

 

[Robertt24]

actually I have swapped out three rear drive shaft sections with no vibrations I also sink the U-joint in used oil to lub it, rust belt takes its toll as the joint is exposed to plash salt

okay I see, so there’s dots going through the whole propshaft which you have to line up?

 

[russcoop]

If you get just the rear section let us know how it turns out

 

[kaboom28]

okay I see, so there’s dots going through the whole propshaft which you have to line up?

When the drive shafts (two pieces) are first put together at the manufacturer, the entire thing is high speed balanced. The balancing is done by welding on pieces of metal onto the shaft. Once balanced, if you were to separate them, you need to put them back together the same orientation, otherwise it’s very likely they would be unbalanced and vibrate. Therefore mechanics would put ink dots on the two halves for alignment when they separate drive shafts so that they can put them back together properly. Your drive shafts may or may not have these dots.

 

[A930rocket]

This u joint from was posted at one time to replace the u joint on the driveshaft.

GMB 220-1670 Universal Joint https://a.co/d/dMvSvIw

 

[russcoop]

Looking at the rear section weight is added at the U-joint an none on the rest of the shaft, so the U-joint must be the primary balance point , chances are he may get by if dollars are thin

 

[Robertt24]

thanks everyone for the advice,

so would you guys prefer just getting a whole Propshaft just to get rid of all the headache and maybe even spending more at the end of the day?