Driveline Vibration (HELP!)

[mgbman69]

Ok guys...

My Ti has been having a vibration bellow the cup holders while under acceleration in 2nd gear.
After searching the forums I decided to change out my center support bearing and my guibo. Everything went well and fit back together without trouble.
The problem is... ... The vibration is still there

It only happens under acceleration in 2nd gear from 2500-3200 RPM...

Any ideas would be awesome. I'm at the end of my rope with this issue

Thanks in advance

[cooljess76]

ummm... transmission mounts, motor mounts?

[b.u.ti-ful]

Is that around 45 mph?

That is where alignment issues usually reveal themselves.

Especially on new pavement.

If so, I would have the ball joints checked.

[Xenocide]

Its not alignment if it comes from the middle of the car, especially RPM based.

I suggested to him over the phone we change out the tranny and motor mounts. Maybe he can get some and drive up here we can swap em out.

[b.u.ti-ful]

Originally Posted by Xenocide

Its not alignment if it comes from the middle of the car, especially RPM based.

I have to disagree having just had vibration all over the car that was fixed with a new right side ball joint.

It isn't RPM based if it is only in one gear.

You hit that same RPM in every gear.

You can test the ball joint theory to some degree by driving the car to the vibration point and then making a left and right swerve.

My whole car would shudder until I swerved it and then it would go away and come back after a straight stretch.

You can also try riding the brake while you are at the shaking speed.

Again, doing this quieted down the shuddering on my car even though it wasn't a brake issue - it was the balljoint.

I am in no way saying that's definitely what the problem is with your car, but those are two free tests to try on a quiet road.

[CirrusSR22]

Is this only under hard acceleration? I had pretty much the same thing in 1st and 2nd at around 3,000 rpms. I replaced the center bearing, guibo, trans mounts and engine mounts and it still was an issue. Then I did a manual swap and the symptom went away. The old driveshaft had noticeable play at the rear u-joint. If you get a chance, remove the driveshaft, or find a way to get just the rear unhooked from the diff and twist it by hand. I don't think you'd be able to feel play while it's still bolted to the diff; unless the play is really bad....

[Xenocide]

Hm U-joint didn't cross my mind. He already has a manual transmission. That would not be a bad thing to check. As for alignment, it could be that. He has control arms, just hasn't put them on yet. In my experience you would feel that in the wheel though.

[mgbman69]

Thanks for all the ideas...

It's NOT ball joints. They have zero play and ball joints don't make an isolated rattle in the tranny tunnel under the e-brake.

After getting under the car the engine mounts and tranny mounts seem to be in good shape. No cracks that I can while moving the engine around with a jack.

I'll do the u joint test tomorrow and see what I can tell.

keep the ideas coming

[b.u.ti-ful]

Check the exhaust mounts - especially the weird horizontal one at the mid-section of the car:



Also be sure the heat shields are not touching anywhere.

[Xenocide]

Its a rotating mass sort of vibration, nothing related to exhaust.

[mgbman69]

yeah, the exhaust mounts are all in great shape and the vibration happens with the heat shields in the car or out.

[b.u.ti-ful]

I still think it's the heat shields.

[Xenocide]

and i still know your wrong.

[roadrash]

Does this mysterious vibration make enough noise to be recordable?? If so, an audio recording might help diagnose the issue.

[minicoop900]

is the guibo ok? we had a customer with vibration in only 1st, changed the guibo and it went away/

also, while its vibrating, push the shifter to the left or right just a little and try to see if you feel anything in the shifter itself.