Rotational play in prop shaft, need help diagnosing

[Tim Allen]

Hi everyone.

I know that this subject has been around quite alot, and after hours of going through all of the posts, I am still no closer to knowing how to fix the problem.

When I am driving my car (A4 B5 1.8t Quattro Sport), when i take my foot off of the accelerator, I get a clunk sound come from the middle/rear of the car. This also happens when I am changing up or down gear. I have been under the car, and notice that I can rotate the prop shaft a fair bit. This is with the handbrake on, and even when in gear. My theory is that this "clunk" happens when the propshaft is kind of "taking up the slack" so to speak. I have read that it is normal to have some rotational movement, but how much is normal? I have a video of the amount of movement. Perhaps someone could tell me if this is a normal amount?

I have also noticed that if I pull down on the propshaft (where it joins the rear diff), I can see movement at the mount bush. This can't be normal right? I am under the impression that it should take a fair bit of effort to see any movement.

My biggest fear is that my rear diff is on its way out. I am able to remove the old and fit the new, but finding one could be my biggest issue. the number stamped on it is DAJ 05109. If it comes down to having to replace the diff, would any DAJ diff fit, or would I have to get one with the exact same part number?

Thanks in advance


https://youtu.be/ax531R_cVz0

[Rob69]

I think your prop shaft backlash looks ok, if the diff was on its way out you might also hear a whining noise getting louder the faster you go. It's probably just the mount bush that needs changing.

[Tim Allen]

This is what I am hoping for. I dont hear any whining noise from the back end what so ever. There also seems to be alot of movement in the center support bearning. I get no juddering from it at all, but can push the prop shaft up and down, side to side really easily and feels quite spongy. That sound normal, or should it be changed? Seems quite a tricky job to do.

[zollaf]

all looks and sounds normal, including the centre prop bearing. what you have is a worn nose bush on the diff, the one at the very front of it, but also check the 2 at the rear. the nose one can be rectified with a new bush from audi. there are no aftermarket ones for it, unless you spend silly money on one. mind you, the genuine one is not much cheaper. other option is to get the plates that go in top and bottom of it to stop it moving about. this is what i have done on my s4, but i made my own out of some ally plate. look at 034 motorsport , jhm or i think apr tiuning for ideas.

[Tim Allen]

all looks and sounds normal, including the centre prop bearing. what you have is a worn nose bush on the diff, the one at the very front of it, but also check the 2 at the rear. the nose one can be rectified with a new bush from audi. there are no aftermarket ones for it, unless you spend silly money on one. mind you, the genuine one is not much cheaper. other option is to get the plates that go in top and bottom of it to stop it moving about. this is what i have done on my s4, but i made my own out of some ally plate. look at 034 motorsport , jhm or i think apr tiuning for ideas.

This is just what I wanted to hear! Nice big smile on my face knowing that this isn't going to cost me tons of cash and time.

When you say that you made your plates out of ally plate, was it basicly cutting some down to size effectivly creating 2 washers/shims? I have some ally plate sat in the shed (about 2mm thick).

I have looked on 034, and jhm, but can't find anything (apart from tons of other parts that I now want) haha.

Just got off the phone to Audi, and after finding the part for them online, they quoted me £138 + vat for it. Think I will go with the ally plate idea (if it really is just creating 2 washers to fit).

[zollaf]

for the life of me i cant find the spacers on the net. basically, once the bush is removed you fit some spacers top and bottom to take out all the play. they are u shaped and just slot in. JHM do a solid mount which is basically the same, 2 u shaped black ally bits. apikol make a replacement mount but its expensive. plenty of other bits to spend money on as you have found.. :)

[Tim Allen]

for the life of me i cant find the spacers on the net. basically, once the bush is removed you fit some spacers top and bottom to take out all the play. they are u shaped and just slot in. JHM do a solid mount which is basically the same, 2 u shaped black ally bits. apikol make a replacement mount but its expensive. plenty of other bits to spend money on as you have found.. :)


So something like a power ring then just made from ally? http://www.ringer-racing.com/product.sc?productId=14


(http://www.ringer-racing.com/product.sc?productId=14)

[zollaf]

yep, thats the kiddie, i saw it on jhms page. the one i copied goes above and below the mount. once you have the mount out it all becomes clear, as its a solid moulded unit and the rubber goes soft allowing it to move. i compared mine to a much newer one a while back and there was a big difference. the new one would hardly move. mines not torn or anything, just old and soft.

[Tim Allen]

yep, thats the kiddie, i saw it on jhms page. the one i copied goes above and below the mount. once you have the mount out it all becomes clear, as its a solid moulded unit and the rubber goes soft allowing it to move. i compared mine to a much newer one a while back and there was a big difference. the new one would hardly move. mines not torn or anything, just old and soft.

So do I just remove the mount, and add the made up plates each side of the rubber? Or do I completely do away with the rubber and build the plates up until they get to the right hight?

[Tim Allen]

Actually, I have just found an install guide. Only question I have now is did lock the 2 plates together?

http://www.vaglinks.com/Docs/Audi/B5/Purems.com_STB5DMT02_Installation_Lo_Res.pdf