So, how long until my driveshaft explodes?

[K20RI_211]

Hey R3V,

I have an '87 325is. Vehicle has new guibo and CSB as of the last year. I've noticed over the last few months that when cold and accelerating in first and second, I get a thump-thump from dead-center of the car - almost felt like it was coming up through the seat. It goes away when the car is fully warm.

Research indicates that this is likely the u-joints binding up under load. Here's my "first world problem": I've got a trip planned to Team O'Neil in New Hampshire this coming weekend to do their winter driving school and was planning to take the E30 (it's my project car, E46 is the daily).

So, how bad of an idea is it to tempt fate and drive this sucker into the boonies and then practice winter driving technique on a slalom?

If you recommend replacing the driveshaft, recommendations on re-manned units that can ship to the Rhode Island area quickly are appreciated.

Thanks,

Jeff

[berlow94]

The e30 driveshafts are balanced. Is it possible when you pulled it to do the guibo and bearing you didn't put it back in the same orientation?

[K20RI_211]

The e30 driveshafts are balanced. Is it possible when you pulled it to do the guibo and bearing you didn't put it back in the same orientation?

Certainly possible. The shop I used to visit was run by a knowledgeable gentleman usually under the influence of....something. Seemed to change with the day of the week.

If that is the case, is it reversible or has damage likely been done if it wasn't re-installed correctly?

[CarsSuck]

If you've got the time, I would check to make sure that the front and rear shafts are properly aligned. The u-joints are supposed to be offset from each other. It doesn't sound like the real problem but who knows how your mechanic did his work.

Have you checked to make sure all the guibo/trans flange bolts are tight? If they get loose it will sound like what your describing. That's what I'd put my money on.

Are you going to do the work to the car, or were you planning to take it to a mechanic?

[K20RI_211]

If you've got the time, I would check to make sure that the front and rear shafts are properly aligned. The u-joints are supposed to be offset from each other. It doesn't sound like the real problem but who knows how your mechanic did his work.

Have you checked to make sure all the guibo/trans flange bolts are tight? If they get loose it will sound like what your describing. That's what I'd put my money on.

Are you going to do the work to the car, or were you planning to take it to a mechanic?

I go to a new place now, right by work. Usually just drop it off and they poke around - have had great luck with them.

I like where you're going with this. If the driveshaft were on the verge of utter and spectacular failure, wouldn't I notice vibration consistently, all the time?

I can check that, but I'm also having some fuel lines replaced and other such work tomorrow, so I'll have them check that out as well.

[jlevie]

On the assumption that the previous CSB had a failed rubber mount, the thumping under acceleration is from bad u-joints in the drive shaft. It will get worse and the more acceleration it is subjected to the faster the drive shaft will degrade.

Getting one quickly should not be a problem. Bimmerworld can probably get one to you in a few days (maybe even overnight). I would certainly replace that drive shaft before I took the car to a driving event.

[K20RI_211]

On the assumption that the previous CSB had a failed rubber mount, the thumping under acceleration is from bad u-joints in the drive shaft. It will get worse and the more acceleration it is subjected to the faster the drive shaft will degrade.

Getting one quickly should not be a problem. Bimmerworld can probably get one to you in a few days (maybe even overnight). I would certainly replace that drive shaft before I took the car to a driving event.

The CSB and guibo were done preemptively; in other words, no such noises had revealed themselves prior to their replacement. The guibo was so-so but hadn't completely collapsed at the point of replacement.

I don't disagree with you - just FYI, if that changes your opinion at all.

[jlevie]

Okay, but unless you put it together wrong thumping from under the car under brisk acceleration (especially in the lower gears) has to be binding u-joints.

[K20RI_211]

Okay, but unless you put it together wrong thumping from under the car under brisk acceleration (especially in the lower gears) has to be binding u-joints.

In thinking over the timing of things, there's no direct correlation between the replacement of the CSB and guibo and the thumping sound. A good 3-5 months had passed after they were installed before the thumping occurred.

The car will be in the shop tomorrow so they will inspect; Turner Motorsports is nearby and can likely get a driveshaft shipped to me in time if that is the culprit. We'll see.

Thanks for the opinions - welcome others!

[K20RI_211]

New driveshaft en route from Driveshaft Specialists of Texas; will be in Rhode Island tomorrow and installed Thursday. Vibration caused by blown CSB which, as mentioned earlier, was new last year.

This will be a lot off of my mind once it's done and I begin the weekend's journey, which consists of a lot of rural driving. Thanks for everyone's feedback.