new drive shaft

[Jim Spence]

I haven't seen this addressed, and a search brings up multiple threads but none that I looked at deal specifically with my question.

I've discovered that I need a new drive shaft. The car vibrates slightly between 25 - 30 mph when I'm accelerating, but other than that it's flawless. I just got the car out of the shop for tie rod ends, and my mechanic had the entire drive shaft out to find the problem. He told me to "get on the net" and find a good remanufactured shaft.

So far I've found two sites that offer remanufactured shafts for around $340 (not counting the core charge). Does anyone have any recommendations on sites that may offer something? '93 325i automatic.

I appreciate any help.

Thanks.

[Pirate_copy]

Hey buddy

You sure it is the driveshaft and not the guibo (flex disc)?

[Jim Spence]

absolutely sure ... they had the entire drive shaft out and inspected everything

[Pirate_copy]

Doh!

[E36 Phantom]

Out of curiosity, what exactly did he say was wrong with yours? Out of balance or what? As for where to find one, no clue. You may want to try wrecking yards though, it may be cheaper than finding one on the net. Of course, you'd want him to inspect it first most likely, but it may be worth a shot.

[jasonf860]

Typically the problem is not the driveshaft itself, but the u-joints it contains. Failing u-joints would cause this exact issue. Problem is BMW decided that their driveshaft would not have replaceable U-joints like most cars do, thus the reason he needs a new driveshaft.

Here's a place to try:
http://www.vacmotorsports.com/
Might be a bit more expensive, but the U-joints are serviceable afterwards.

[Jim Spence]

Phantom, it's out of balance. It may very well be u joints, but as Jason pointed out it's a "one piece" apparatus.

For the time and trouble it'll take to find one parted out, take it somewhere and have it tested, then have it installed with absolutely no warranty, I think it makes more sense to buy a reconditioned one from the net with a warranty and all new parts. I've found two such sites that offer it totalled reconditioned with 12 month warranties for around $340. It looks like this is where I'm going.

I was just hoping that someone had a good experience buying one somewhere and would pass on the info.

Luckily this only affects the car at very low speeds under heavy loads, i.e. going uphill in a residential area or pulling out from a stop light quickly. Once I get up above 30 mph or so it doesn't do it, no matter how hard I get on it.

To be honest, it's probably saving me money in gas; I now have a tendency to accelerate slowly from a dead stop.

[jasonf860]

Out of balance? Hmm... Since it is a 2 pc unit, I bet it wasn't lined up properly or a weight fell off. If they checked it on a balancer, then the addition of the correct weights would fix the issue providing it's not the U-joints as I mentioned earlier. BMW also sells weighted bolts for the diff input shaft to counteract an out of balance driveshaft.

[Jim Spence]

Wouldn't an out of balance drive shaft vibrate at all speeds? Especially higher RPMs.

Just curious.

[Andycapps]

Wouldn't an out of balance drive shaft vibrate at all speeds? Especially higher RPMs.

Just curious.


+1

I think if the actual drive shaft was out of balance, it would be more noticable at higher speeds. If it IS indeed in need of a drive shaft, I'd go with the aftermarket deal with the replaceable u joints if you plan on keeping the car a while. I'd stay away from anything salvage- as you never know what condition its in or how long that ones gonna last. Regardless if it looks ok at this point .i would go ahead and replace the guibo as well.

[jasonf860]

+1

I think if the actual drive shaft was out of balance, it would be more noticable at higher speeds. If it IS indeed in need of a drive shaft, I'd go with the aftermarket deal with the replaceable u joints if you plan on keeping the car a while. I'd stay away from anything salvage- as you never know what condition its in or how long that ones gonna last. Regardless if it looks ok at this point .i would go ahead and replace the guibo as well.
If you go with VACmotorsports, their remaned driveshaft comes with a pre-installed center support, and a guibo. Plus their u-joints are serviceable.


And yes, and out of balance driveshaft would vibrate all the way through, however like a wheel that is out of balance, it will find a "smooth" spot at a certain rpm. That's why a tire balanced to 70 MPH is not necessarily still in balance at 100.

[Pirate_copy]

If you go with VACmotorsports, their remaned driveshaft comes with a pre-installed center support, and a guibo. Plus their u-joints are serviceable.


And yes, and out of balance driveshaft would vibrate all the way through, however like a wheel that is out of balance, it will find a "smooth" spot at a certain rpm. That's why a tire balanced to 70 MPH is not necessarily still in balance at 100.

+1, resonance is an odd thing

[jasonf860]

Nvh Ftw!