Vibration while acccelerating

[Rami93]

Hello all, I am having a lot of vibration that seems to be coming from the rear wheels. I checked the engine mounts and they seem fine. I just changed the transmission mounts and that didn't help much. I also had an alignment and balancing done and still nothing. The vibration happens at low speeds while accelerating and goes away around 3000 rpm and stops when I put the car in neutral and let it coast. On the highway its not noticeable at all, the car runs smooth. What could be causing this? Thanks, Gio

[teen ti]

U joint in the driveshaft


Edit: Link to what I went through
http://www.318ti.org/forum/showthread.php?t=36643

[Rami93]

where did you get the U joint ? And does it have to be welded ?

[teen ti]

you can't get a u joint by itself since they're staked in from the factory, you pretty much have to get a new driveshaft

[Rami93]

ok thanks

[zoner]

A reputable drive line shop could replace them for you (it's definitely not something you could do yourself), but then you also have the center bearing that is a wear item, yoke bushing, lock nut, balancing, etc. and by the time you're through, you're probably spending as much, if not more, than just buying a replacement drive shaft outright, which is why people don't even bother- they just buy the rebuilt shaft. Don't forget to replace the giubo (flex disc) and corresponding nuts/bolts when you do it.

Expect to pay $350-500 for a replacement shaft but once it's done, you're good for another 100K+ miles.

[Rami93]

My car is manual so I would have to get one from a manual transmission right? And If I would get ahold of a shaft would I be able to install it myself? Or would a mechanic have to do that ?

[zoner]

Yes, you would need a shaft for a manual car.

If you are mechanically inclined and have some experience working on cars, it is not an exceptionally difficult procedure, but it is rather tedious (expect to spend the better part of a day) as you have to drop the exhaust system from the head pipe rearward, drop the transmission crosssmember, and remove all of the heat shielding from underneath the car before you even get to the point where you're beginning to remove the driveshaft. If the exhaust bolts between the exhaust manifold and headpipe are rusted bad enough, those can be difficult to remove or they'll just snap and then they're really easy to remove!

It doesn't require any special tools but it does require a fair amount of patience and being mindful of the order in which things are removed and the order in which they are replaced. Preloading the center bearing on installation and installing the front six bolts in the correct directions are about the only special procedures that you need to be aware of (that I can think of off the top of my head).

[Ralliart10]

Can you install the driveshaft in one piece and not take it apart?

[zoner]

Originally Posted by Ralliart10

Can you install the driveshaft in one piece and not take it apart?

That is the preferred method. There is no reason to take the driveshaft apart unless you are only replacing the center bearing. Once you take it apart, you risk throwing the entire shaft out of balance which is why if you are going to take it apart, it is critical that you CAREFULLY mark both halves of the shaft so that you can line it back up in the correct position on reassembly.

If you are installing a new/rebuilt shaft, install it as one piece.

[Rami93]

I'm thinking of buying the drive shaft on ebay from Bavarian parts. If I would get the rebuilt shaft would the flex disc be the only part I would have to replace ?