Rear Axle Swap Pinion Angle XJ vs. MJ

[comanche09]

Can I use the same pinion angle for an XJ with my MJ?

 

Got the Mopar perches coming in the mail for the XJ 8.25 axle. I'm keeping a SUA setup. Can I parallel the mopar mounts with the OEM XJ (same angle)? Or do I need to adjust. I will be installing 3" lift leafs or MT springs from Hellcreek eventually down the road, but just swapping MJ 4x4 springs in place of original 2wd springs for now. Thanks!

[TrailReadyMJ]

You will need to set them up for your truck and suspension setup. XJs have a shorter wheelbase, different springs, different mounts, etc.. etc... It may end up being close, but setting it up separate will save you a likely headache down the road.

 

In case you don't know already... If you don't have a SYE and CV shaft, keep the pinion and t-case output almost parallel (about 1-2* lower is ideal due to the natural axle wrap you get with leaves). If using a CV shaft, point the pinion about 1-2 degrees below the output of the t-case, basically pointing it right at the output yoke.

 

Of course MJs don't require an SYE like XJs do. I'm at 6" without one and have no vibes at all, at any speed.

 

Hope this helps!

[BORDENCOMANCHE]

wait a second here?

 

Just finishing my 4x4 swap with the Comanche, using XJ parts, I didn't need no 4x4 springs. Whats the dealio here?

[Geonovast]

You may be able to get away with using the same pinion angle if no SYEs are involved... but I would set up your perches correctly. The distance between the perches on XJs and MJs is different.

 

 

Cut the XJ perches off, and bolt everything together somewhat snugly. Make sure your axle is centered, and set your pinion angle. Tack the perches on, pull the axle back out, and finish weld them.

 

wait a second here?

 

Just finishing my 4x4 swap with the Comanche, using XJ parts, I didn't need no 4x4 springs. Whats the dealio here?

 

MJs had different springs for 4wd and 2wd.. the 4wd ones sat a bit higher, that's it. You don't need the 4wd springs to have 4wd.

[Blue XJ]

I would measure the axle that your current ones are at, and install the new ones at the same angle, assuming you aren't changing your ride height at the same time.

[comanche09]

Thanks for the replies guys :cheers:

 

I was hoping to be able to just weld em up and install in one step, but better to avoid headaches and follow your advice.

 

Speaking of welding... Is it safe to weld on the tube with the diff fluid drained (explosive gas)?

[Blue XJ]

Speaking of welding... Is it safe to weld on the tube with the diff fluid drained (explosive gas)?

 

yup, its safe