7.5 to 8.5 rear driveshaft question

[gto78]

Not to side track this thread too much further, but on the topic of hard to find vibration- I had a slight vibration problem that was kicking my *ss basically. We balanced everything twice... rotated tires, double checked road force variation with the balancer, etc. and it ended up being a front brake disk that was out of balance. I knew the disks were getting old and right at the wear limit so I didn't feel bad taking a chance installing new ones. The new ones cured the vibration issue.

 

[84GP455]

Well of course that makes sense, as the metal wears off the rotor it becomes more unbalanced.I had this problem with my pickup it had a vibration on the highway and i had new tires balanced and installed but it did not go away until i changed the front rotors because they were old. I have all new brakes all around on my car, rotors, calipers, pads, drums, shoes and spring kits and even new wheel cylinders. I did all the work myself and the car stops on a dime.

 

[DrRansom442]

don't forget the thinner the rotor is (assuming yours have been turned atleast once) the easier it is to heat warp a rotor (just ask Grand Cherokee owners with those stupid composite rotors that seem to warp just staring too hard at them). Regaurdless what increases teh runout on a rotor ... it will cause vibration issues. Vibration diagnosis sucks *ss. It's often hard to isolate ... especially in older cars where stuff seems to be loose everywhere anyways.

BTW, if you could SEE noticible dents in the driveshaft - I'm a tad surprised they even tried to balance it. I second the GN driveshaft for simplicity ... buy it and some good U-joints be done with it. Why cut something that doesn't need cut?