Just had a new Coast 1310 Rear Driveshaft installed, and looks like my pinion angle is off. Having driveline vibrations between 60mph - 65mph. Have Teraflex Rear UCAs, but it appears that the rear Uppers are made in two different lengths - a long one to be used with rear adjustable lowers and a shorter UCA to be used with stock rear LCAs. Apparently, I have the long one, and it's currently been shortened as low as it'll go and I need it to go shorter to get the pinion angle right.

One option would be to go with adjustable Lowers and push the axle back and get the angle right. And I was told that I could go back to the stock uppers. Thoughts? Can I have a machine shop cut and grind the arm shorter and clean the threads out or would that weaken the control arm?

 

I don't think you need to shorten the uppers if you pick up some lowers. That would actually help center the tire in the wheel well. Your after market DS should have enough travel to be lengthened via LCA.

 

I agree with you on that - I was just trying to see if there was an option without having to invest in a set of rear lowers to do this. I plan on eventually filling in the blanks with Teraflex Rear Lowers and Front Uppers.

 

Get the adjustable lowersand be done with it. Waste of time and money to start cutting and welding on the uppers.

 

Sure seems like I've done a LOT of that lately

 

I feel your pain! Doing an upgrade and then finding out you need another to get it right. Everyone here knows the feeling, but when it's all said and done, your JK will be built right!

 

Haha, hear that!

 

Bad thing is when you buy the parts from a reputed place AND have them install it, only to find out it was the wrong part installed that's causing this grief