Here is my current rear pinion angle. It is set about perfectly inline with the rear drive shaft.



I am wanting to lower the pinion a little (-1 to -2 degrees) to help with re-adjusting the rear coil spring bend I have to regain a straighter coil.

Raising the rear pinion was easy using a bottle jack under the differential. What is the easiest way to lower the pinion angle? Adjusting the UCA's is no big deal but the part where I actually rotate the pinion might be tricky, I am thinking.

Open for comments.

Thanks!

 

I'm a little confused about what you are trying to do here. You mention using a bottle jack to lift it... are you just asking about how to droop the axle?

What I thought you were asking was about how to have less bend in your coils. The answer is simple and has nothing to do with your pinion angle. You should keep pinion as is and instead cut off and rotate your coil perches.

 

Correcting the perches is the correct answer but if you insist on putting the pinion back down then why not use your bottle jack with a small 2x4 on the bottom of the tub to push down? You'll need to have the arms loosened, potentially one set removed. I've not had to adjust my pinion.

 

I agree that relocating the perches is an option and maybe even the best.

But, I have read that the proper angle for the rear diff is -2 degrees down. Is this correct?

I am looking for the best way to rotate the pinion angle back down. When I rotated it up I just placed a small jack under the pinion side of the rear diff and raised it to its current angle with the drive shaft. Easy. Now, toying with the idea to lower the pinion angle back down a bit I am looking for a way to do that since I certainly cannot put a jack over the pinion and push the front down.

 

Okay, you are correct that it should be 1-2 degrees down from being in line with the transfer case output because under load, the rear pinion will rotate up.

 

Good idea.

I'm not sure what a couple of degrees might get me. It's all trial and error based on chasing perfection to meet my Jeep OCD.

 

Do this, loosen the lowers
Get the axle on stands
Remove tires.
Remove uppers and support pinion at -2
Loosen jam nuts on upper arms
Take the Ds Arm, bolt up frame side and adjust axle side to mount. Both bolts should slide through the mount easily.
Do the same with the PS.
Tighten everything up
Done

 

I adjusted my pinion this weekend. I also just had to change it a couple degrees and wanted the fastest, easiest way so here's what I did. (I only adjusted my lower arms because I didn't want to deal with taking the wheels off to get to the uppers for a 1-2 degree change.)

With jeep on ground as normal place factory jack under pinion and raise it so it just touches the pinion.

Remove both lower control arms. They were under no tension and came out easily. If they are under tension I would only do one at a time.

Lower jack slowly. In my case the pinion stayed put so I pulled it down by hand, rocking it a little I was able to get it to come down. If it goes too far raise it again with jack.

Measure bolt holes distance once angle is good and adjust arms to that length.

Reinstall arms.