I'm sure there is a good reason why Chrysler didn't put a high pinion in the rear of our JK's like they did in the front. Anyone??

I have an 07 2 door X, I'm running a 2.5" Terraflex coils & shocks. Plus I added a 1" puck in the rear only. 35" tires.
Running the stock drive shafts.

* Is this setup going to fail?

* Must I tilt my diff upwards, if so, do I have to buy an aftermarket DS or will my stocker be OK once I tilt it & shim my springs?

* I'm thinking about lengthening my rear upper controll arms myself. Might even make them adjustable. Is this something you guys are doing? Are they made out of pretty thick steel? At least I could cut them in half, reinstall both halves. Raise the diffso that the pinion points towards the TC, measure the gap, weld in proper length piece. Sounds a lot cheaper than buying aftermarket.

* If I extend only the rear upper controll arms, will that also move my rear axle back? Closer to the "pre lift, stock location. (Centered in wheel well) Or would I have to lengthen the bottoms as well?

Thanks in advance for your time & knowledge.
Bruce

 

I don't have any data to back it up, but my gut feeling is the low pinion in the rear is stronger than a high pinion in the rear would be.

I also believe the opposite is true for the front axle, the high pinion being stronger.

 

You have a 2 door or 4 door ???

That lift is OK for 4-door rear shaft ... your pushing it on a 2-door ...

I just installed a CV DS, JKS upper arms and JKS adjustable perches to go with my 4 inch lift my 2-door.

Even if you buy tilt the axle with adjustable upper arms you are still gonna have a severe angle at the TC so it will fail there eventually ....

 

I see!

It's a 2 door. I was afraid you'ld say that. So the Tom Woods would be the answer as long as I tilt the Diff?
Thanks

 

there is more pinion deflection with a high pinion in the rear, and opposite for the front, high pinion rears to bust ring and pinioins.

this is why it is common for tj owners to put a high pinion dana 30 in the front to increase strength.

 

Good to know. Thanks for your reply!!

What about cutting & welding the rear upper controll arms? Is this a common DIY project?

 

What is the direction and cause of the pinion deflection?

 

The R&P is stronger when run on the drive side of the gear as opposed to the coast side of the gear. When running on the drive side, the gears are pulling themselves together. On the coast side, they're pushing apart and under torque and deflection the gear mesh rises up the tooth. This weakens the gear as the load is now on a thinner portion of the gear tooth. I've never seen a HP 44 rear survive any length of time. The guys that I know that have run them replaced R&Ps yearly.

 

Thanks for the reply. New ther was a reason, just didn't know what it was.

So, if I tilt my diff up, will that help my stock DS last longer?

Thanks

 

This sums it right up. Thanks you.

Really, I should do exactly what you have done. Did you have to take the entire axle housing off jeep to grind the spring perches off?

Thanks