carrera 3.2 ROW rear thumping noise troubleshoot
 

Hey guys

My mechanic and I have been trying to resolve noise from what sounds like right rear only in hard right turns, so 911 loaded to left in right turn. Its a thumping noise.

Sound started several weeks ago. I noticed oil spray at half shaft right side at tranny and found to be tranny leak so axle flange seal was replaced.

Soon afterwards the sound developed and progressively got worse. First it was only on hard slow speed right turns and then developed into higher speed right turns.

Everything was checked left and right; axles, CV, wheel bearings, struts, sway bars. Seemed that CV joints could be culprit and noise often associated with CV. The right half shaft was stock with 138k, the left was replaced in 2012. So right half shaft was replaced. Afterwards the sound is still there only apparent in very hard right turns at slow speed. One other troubleshoot item, I determined noise only when in gear, if in neutral in turn no noise.. I lifted car and pulled wheel and checked all torques and play. No leaks, damage, play in wheel or anything I can see with my limited skills.

any feedback appreciated

John

Hi John have you checked the trany mounts and bolts?
ivan

I'd change the wheelbearing. 9 out of 10 times it the source off noise. Even of there is no play.

Good point Denis ..John,; how did you check the rear bearings?

Also is it a clunk ?
Ivan

I did not check the tranny mount, will check that.

When my 911 was on jack stand in neutral break off no play in wheel that I could feel, with wheel off no play either with wheel assembly.

We discussed wheelbearing as an option. Mechanic thought wheel bearing noise can sound different but not ruling it out.

Perplexed why the noise in gear and not in neutral.

If the bearing is bad could the extra torque when in gear help to create the noise?

Hope to get this resolved before my first AX in mid march.

As a side note this was the first time I ever had my 911 up this high and was underneath fiddling around, hope to do/learn more, really debating a higher lift and at least front jacks.

thanks!!

When the axle seal was replaced was the trans oil drained and refilled? Do you have a limited slip differential?

I dont have and LSD and I believe he tilted the car for axle seal so only partial tranny oil replace/ top off

I had a similar issue and what I figured was a wheel bearing turned out to be a seized caliper. Similar sound, same load circumstances. Swapped with new calipers and pads from Porsche and it was gone. Good luck.

Well I had the car up and looked at it more. Couldn't see anything.

My mechanic had the rear brake and rotor off, the axle out, the stub axle out, checked diff and bearings, checked trans oil, no luck. He checked droplinks and straightened one (I saw one slightly angled). He checked all wheel bearing and found a worn right front wheel bearing. It wasnt real bad but a little noisy so replaced.

Still driving slight thump in hard right turn. And still has to be in gear under power, if hard right turn in neutral not heard. Makes me think diff issues even if not apparent? My first AX is next weekend so would love to have this not making a noise while hammering cones...

Will put the car up again today so see if I pick up anything..

and the mounts ??

tranny mounts?

i dont believe they are stock and were replaced about 35k miles ago. the car is up as i write this, checking and trying to find torque numbers, main mount bolt and two small locking nuts it appears.

Ditto on rear wheel bearings.
 

I just pulled both cv shafts due to what sounded like diff bearings. Both cv joints were spent with one being about 1/4” slop..
Both wheel bearings spun freely and with lots of noise. I am shocked I never heard them.
Pelican has all the parts and I earn one more sticker...Yay!

well if its CV I could have a bad left half shaft since right is brand new. Left was replaced in 2012 so thinking its not the left shaft but......