engine and drivetrain car shuddering at 40mph

[larryt]

hi all,

 

i have already replaced my gearbox mount, but the noise continues at 40mph, only when im giving it gas, if i back off the gas the noise stops...

[Jace]

car too low?

[larryt]

car too low?

 

 

i have already raised the car at the back and the noise is stil there

 

p.s. no such thing as too low

[xferboy]

center support bearing? I had similar

Edited April 22, 2015 by xferboy

[larryt]

can anyone advise me if an e21 center bearing would fit?

 

im really struggling to get parts for this car in the Uk

[jgerock]

can anyone advise me if an e21 center bearing would fit?

 

im really struggling to get parts for this car in the Uk

Jaymic should have everything and more.

[John_in_VA]

but the noise continues at 40mph, only when im giving it gas, if i back off the gas the noise stops...

 

In every gear (2nd, 3rd, 4th)?

[PaulTWinterton]

Shudder or noise? To me they are different.

If it's a noise:

Another possibility is that your center resonator is hitting the floor underneath. Not usually at speed, usually on hard acceleration, but it's easy to determine(and eliminate).

Looking under the car you should have approx. 1/2" between your resonator and the floor at the closest spot, which is the edge of the tunnel, by the rear passenger seat. If it's less than 1/2" the torque of the engine can force the exhaust to touch and vibrate. You'll see marks if it's been hitting.

Adjusting the clearance is easy. Loosen the "donut" fitting ahead of the resonator. Loosen the clamp ahead of the rear muffler, twist resonator to achieve clearance. I wedge a piece of 1/2" wood at the clearance point, tighten fittings, and remove wood shim.

If it's a shudder: I'm +1 on center bearing.

Edited April 23, 2015 by PaulTWinterton

[larryt]

Shudder or noise? To me they are different.

If it's a noise:

Another possibility is that your center resonator is hitting the floor underneath. Not usually at speed, usually on hard acceleration, but it's easy to determine(and eliminate).

Looking under the car you should have approx. 1/2" between your resonator and the floor at the closest spot, which is the edge of the tunnel, by the rear passenger seat. If it's less than 1/2" the torque of the engine can force the exhaust to touch and vibrate. You'll see marks if it's been hitting.

Adjusting the clearance is easy. Loosen the "donut" fitting ahead of the resonator. Loosen the clamp ahead of the rear muffler, twist resonator to achieve clearance. I wedge a piece of 1/2" wood at the clearance point, tighten fittings, and remove wood shim.

If it's a shudder: I'm +1 on center bearing.

when i think of it, i did notice the other day that the u clamp for the rear exhaust section has moved where its caught the floor somewhere.. i will have a look at this at the weekend and try to eliminate it

[larryt]

also would someone be able to advise the best way to change this center bearing, ive managed to track down the right one and was hoping to tackle it this sunday on my drive.. if its going to be a huge job for a driveway then i will have to find a garage who are able to change it

 

thanks

[Nesset127]

As far as I can understand.. It's not too bad of a job.  Drop the drive line and center support and swap it out. Also, I would advise changing out the guibo while the driveline is out...

[bento]

As far as I can understand.. It's not too bad of a job. Drop the drive line and center support and swap it out. Also, I would advise changing out the guibo while the driveline is out...

The most time consuming part is getting a wrench ground down to fit in and loosen the nut, then making sure you have everything else.

You need a big pipe wrench or bench vise to hold the DS while you loosen the nut. A big breaker bar or pipe will help with that.

Oh, penetrating oil is your friend.

Once you have all this stuff, Nessett is absolutely right. It goes pretty quickly.

It might be worth inquiring if anyone local to you has the modified wrench and is willing to loan it out. You'll probably just use it once and it'll save you the trial and error of modifying one yourself since you're working in the driveway.

[Beaner7102]

Also mark the two halves with a dab of paint, liquid paper or the missus nailpolish - any colour except black .

As they are splined, one tooth out and your tail shaft will be out of ballance and vibrate.

HTH Beaner7102

[Nesset127]

Very good advice aswell ^!

[larryt]

thanks team! i have had a look and im going to take it up the road to the garage and get them to change it, they have replaced them before on other beemers so he is confident they can do it for me in a morning. also what is this guibo that seems to be cropping up everywhere?