2001 911tt, tip.

There is a very noticeable vibration, almost like a grinding, when I am accelerating while cornering. It doesn't appear while driving in a straight line, and it's not noticeable while cornering at a constant rate, only when accelerating. The harder I accelerate, the more pronounced it is.

I took it to a Porsche mechanic- he thought it was due to the front diff. fluid being a little low, so he topped it off. I didn't notice much of a difference afterwords, but my friend did. Lately, though, it's very noticeable. (it could, in fact, have nothing at all to do with the front diff)

Any ideas before I start spending a lot of money troubleshooting? This is my first Porsche and I've only had it for 2 months, so I'm not all that familiar yet. Thanks!

 

Considering when this happens, I'd start looking at motor and transmission mounts.

 

check the trans mounts too.

 

Thanks. Are theses mounts a common problem?

 

We're guessing here, of course. But since someone thought it was your front diff, I'm guessing the sound comes from the front. That would kind of rule out the motor and tranny mounts. I'd be looking at front wheel bearings and maybe the CV joints.

Jon

 

it might be wheel bearings

 

its wheel bearings, change all 4, its a crappy design Ive changed quite a few

 

The sound isn't necessarily coming from the front. In fact, it's more of a "feel." It could be coming from the front or rear- hard to tell.

What does it typically cost to replace the wheel bearings?

 

Unfortunately, it's rather expensive because the labor cost is high. Wheel carriers have to be removed and the bearing pressed out, the new one pressed in. As I recall, standard labor rate is 3-4 hours per bearing. I might be wrong - that could be for the front axles. I've had both done recently.

Good luck.

Jon

 

Yeah its a pain to do...I wrote a nice DIY in the tech section. Everything has to come apart and a lot of careful presswork.

 

Quick follow up- turns out it was the transmission mount- both of the rubber mounts were completely broken inside the housing. The vibration I was feeling in corners must have been the metal to metal contact because there was no rubber insulation in there any more.

 

Upgrade to the 997TT part. It's made better and fits the 996TT.