Ok I'm a rookie with these adj. control arms. I have an 08 four door with a 4" RC that has adj. Uppers and lowers. My caster is a little low at -3.7 but still drives good. But I feel like tinkering so, if I adj my caster with my upper arms is that going to throw out my pinion angle

 

if you shorten up your upper arms (or lengthen your lowers) to give you a bit more positive caster, your ride will feel better on the highway but, there will be more angle at your pinion and depending on what gear ratio (5.13 or higher) you are running and if you have an aftermarket u-joint style drive shaft, you will most likely feel some driveline vibrations.

 

I'm running 35s with 4.88s and a auto trans. I think I'll adj it one or two degree and see what happens. Thanks for the input

 

Isn't it true that the front shaft usually doesn't see high rpms (2H), so you my not experience any vibrations from "bad" pinion angle there? So, if it's a mostly street driven jeep you can sacrifice a little front pinion angle for better caster.

 

That doesn't make sense. It's 2wd that you would see the highest rpm's on the front drive shaft, (highway driving).

It's on the highway that the front drive shaft vibes will cause the t-case to explode.

 

Why is the front shaft spinning at all in 2WD?

 

Never mind... no locking hubs.