So after an auto-x last weekend I found myself with a clunk in the rear end. It kinda sounds like a flat tire or loose rim, and is worst between 20 and 30 mph. It seems to go away after that. Braking and/or cornering or load changes don't seem to make any difference. Sounds like its coming from the passenger rear.

First thought was wheel bearing. ZERO play in either wheel (bearings were new last year). I tightened the wheels down very good as well. Def neither of the obvious problems.

This is where I need some help. I'm thinking it might just be a bad flat spot. There is a bit of a vibration at low speeds (5 mph or so) that feels like one, and the noise is just it getting amplified at the right speed. However, I've never experienced a bad half shaft. I figure that it would sound like a bad CV joint, which in my experience tick more than clunk, but I'm really not sure. I searched and saw broken diff mounts, but shifting doesn't seem to cause it so I think that is out too.

Any thoughts?

 

my vote still is on the diff mounts. Driveshaft probably isnt completely in 100% balance and at certain speeds/rpms causes a vibration and you are getting your clunking from this.

Why would you overlook a broken diff mount anyway? Get that bad boy fixed

 

^Not exactly true, he'll know if he has a broken diff mount. You may be right on the driveshaft imbalance though.

jdmsuper7, your best bet is swapping wheels/tires to eliminate the possibility of flat spots on your tire. An unbalanced wheel will also cause such problems.

 

hey, i have the exact same problem on my fc. Rear passenger side feels like flat tire or rims about to come off. im putting on my stock wheels when i get home, and taking her for a spin to find out if it's the wheels.

Did you figure out what it was???

 

I hate to say, but it fixed itself. Never saw it again all season.

 

Wow. I hate it when that happens.

 

What are you talking about? I should be so lucky if all my car's problems went away on their own!

 

when you had the problem, was your clutch also slipping excessively in 1st? i just got the wheels balanced just to make sure its not the wheel, and it still does it. im afraid of even driving it around the block :s

 

I hate it because now the problem is just hiding, waiting to come out at the worst possible time!

 

No, I was usually in neutral or fully in gear. It wasn't a launch thing at all.

Also, I wish I would have just fixed it and not had it just go away. Ditto on my nasty idle surge that manifests itself every blue moon.

 

Yea... like at a track day. GOTCHA BITCH!

 

Or at the Philly region auto-x this weekend as I wake the car up from her long winter's nap.

 

That sounds like a recipe for disaster. Good luck!

 

i changed my suspension to low milage stock suspension shocks/springs and also replaced my stabilizer links and the problem's pretty much fixed
AAS ACTUALLY WORKS!!!

 

I would get the car up on a lift and check out everything. Sounds like a driveshaft issue...or does it feel like its coming from the tires?

 

well..it was immediately once I put on the new wheels/rubber. i realized the overall height of the new set is about 1.5cm higher than stock. (235/45/17) Do you think that might've been the issue?
I was positive it was a drivetrain issue..OR wheel bearing slightly warn out. After I put in the newer susp. setup, most of the hesitation was gone. Probably just cushen's the vibration more effectively..
A little off topic, but what would be a better size tire for my rear wheels? (17 X8) I was thinking 235/40/17

*sorry for jumping all over the place lol