The Pettitt http://www.pettitracing.com/rx7/index_suspension.htm
urethane diff bushings are quiet "almost like stock" but are also stiffer.
I just installed them Tuesday and really like them.

As others have reported, breaking the 4 nuts on top of the diff is the difficult task. Since I am a small person and do not have super strength, I gave up on the normal methods after a while. I did not want to remove the drive shaft and PPF which would allow rotation of the diff for better access. My remedy was a 2 ton capacity wire cable winch, AKA a come-along.

I conneted the winch end to the side of the frame cross member and the doubled up cable end around my wratchet or box end wrench. The cable was routed as to pull straight as posible. It worked as I thought it would, easy.

 

Not a bad idea. I used a box end wrench and two pry bars - one braced against the frame and one for leverage; this approach is not straightforward - but it does the job also.

 

Very creative.

That is one job that I would not want to do in my garage. I paid my mechanic to do it and had them replace my gas tank (broken baffles) and fuel filter at the same time. Best $400 ever spent. Thanks Vista Brake in Vista CA. Love those guys.

 

The problem with those nuts and long bolts are the factory loctite on them. Get that first turn and you are home free.


Later