Thread: Try diagnosing this... odd vibration/grindingg issue.

'98 GTP w/160k miles... the one in my sig and I'm debating on selling it or keeping it. I just want your guys assessment on this before I make a decision.

I got this car as a total mystery and it had some abuse. It has had right side damage at some point, maybe twice. Once was rather superficial and ripped the sideview mirror off and did some rear quarter damage. The one appears to have bent front control arm mounting point a bit so it's not totally square and the car does have excessive camber on the right front wheel that will have to be dialed out. That said, I don't see anything rubbing or that would cause this.

Symptoms: Car moves and accelerates fine. Grinding noise is heard from the right front at low speeds. As speeds increase to 40mph it becomes a tremendous vibration that jars the whole car, to the point I've driven it less than a mile while testing.

Items replaced:
-Control Arm w/ ball joint.
-Strut and strut mount.
-Wheel and tire (rim from my good GP with brand new tire to see if that helped).
-CV Axle
-Hub/Bearing Assembly
-Pads/Rotors

I'm assuming its the differential blown from somebody playing with burnouts or maybe from the impact. Can a blown differential cause such vibration on the passenger side only, yet still propel the car forward like normal? I have jacked the car up, put it in drive and let the wheels free spin. The same grinding/vibration comes from the right front and increases with speed, and I have no idea exactly where from. I have felt around the tire and even with the camber issue it isn't rubbing any components.

Throw some guess my way.

From my experiance, if it would be a differential issue, it would pull left under 3/4 to wide open throttle. Mine did have a grinding and sluggish feeling before it went out this last time.

Check the rotors and make sure none of them are warped. Make sure none of the calipers are locked up.

Keep in mind to check and replace both sides as you see necessary. Front end noises have a tendency to "throw" the sound to the other side.

Obviously the transaxle is full?
x2 on the differential.
Time to hit the junkyard for a cheap trans or diff assembly.

In theory.. it could be diff and still move. It would be odd though. Typical diff is either blown enough to crack the cover and leak fluid or sit still with no movement.

It's not brakes, I forgot I did put new rotors and pads on it. Also, the grinding only happens on part of the rotation of the axle, not the full time. The thing that really has me baffled is the horrible vibration, which is most definitely the right side. Can a differential cause this vibration?

I wouldn't mind hitting the junkyard for a transmission, if that's for sure what it was. That's what I'm trying to determine.