Shudder under acceleration

[Aytah]

Just wondering what could be the cause of the following problem:

Under moderate to hard acceleration there is a sort of shudder coming from the rear once I pass 3000 rpm then it goes away. I'm assuming the problem is somewhere between the tranny and diff, but it definitely feels like its coming from the rear of the car. The only known issue is that one of my rear winter tires is mounted backwards (which I'm getting fixed this week-end). Could it be the gears in the diff are wearing out (car has 320000 kms on it), or possibly a driveshaft/guibo problem?

Any suggestions are appreciated.

[88325isboy]

driveshaft.

[I_like_E30]

could it be a loose rear-end?

[Rob]

could it be a loose rear-end?

could you be more specific?

[Aytah]

I'm pretty sure its a rotating part since it gets worse the harder I push it. Can the insides of a differential become loose? Maybe a Diff fluid change would help. I just bought the car, but I know that it had a new Diff put in a year ago, thats why I don't think its that.

When they have it on the lift to fix the tire I'll have a look at the driveshaft and diff. I know I should be looking for anything loose, but is there anything else I should inspect?

[88325isboy]

I would have them see how much play is in the driveshaft itself and check the guibo to make sure it is not broken and the center support bearing also.

[NC325iC]

all your guibo bolts in?

[Hick]

Center Bearing!!!! Omg?!?!?!?

[AndrewBird]

Center support bearing or an unbalanced driveshaft. Some times the weights used to balance the driveshaft will fall off making it unbalanced and then it will rip your center support bearing and flex disk apart. Bad part is you have to drop a bunch of heat shields to even see.