So, I had my torsen diff swapped for a TII along with 4.3 gears, nylon bushings and some reinforcments to the PPF done about 2 weeks ago. I went out and did some 40-140 pulls last night, and I have noticed that my car seems to vibrate more above 7k RPMs. My car pulls strong to 8k, but it just seems like it makes a bit more noise/vibrates more above 7k RPMs. Is this typical? Should I be worried about anything else?

 

get a good 4 wheel alignment

 

Ok. Any other possibilities?

 

Isolate symptom..... if only engine RPM is factor as opposed to gears/driveshaft/ujoint/ accell/decell/load ???

 

WAKE UP PEOPLE! He replaced stock rubber bushings with nylon. DOH!

 

Who did your rear end? If the ring and pinion were not setup perfectly you could experience vibrations.

 

Ring and pinions not set up properly do not normally vibrate, but make a loud whining sound.

 

Sounds like the bushings to me, they are stiffer than the stock rubber ones

 

you did not specifically state that the new nylon bushings were differential bushings....

assuming that you did go to nylon diff bushings my opinion is that they are the source of your additional vibration. due to the fact that the PPF connects the engine to the chassis when the durometer of the bushings ischanged, it is similar to changing motor mounts.

i run solid diff mounts and like them alot but they do contribute vibration.

howard coleman