Hi all so heres the back story I have an ‘00 xj with 6.5 inch lift and i just installed long arms on it and did a hack n tap and swapped the tcase bc the ****ty 242 took a dump anyway swapped it for a 231 did a hack n tap on it and I installed long arms. Yea it had short arms with a 6.5 lift and rode like ****. Now it rides better but the drivelines vibrate a bit both of them are brand new. Someone told my pinion angles are off. So just looking for some insight on what they should be or how it should be. Tried to do some research and didnt come up with much dont really understand what it needs to be angled both front and rear. Fyi it had a tcase drop before and was removed with long arm install. Heres some pics from after the long arms wheeling and of the tcase fun lol.






Thanks Clayton

A picture of your pinion angles would help answer your question about pinion angles much more than you sitting on the hood, just sayin...

The pinion angles should be 0-3* of each other, no greater than 3*...you might need to use degree shims on your leaf packs.

Ok I’ll try to get some pictures later and throw and angle finder on it to see what degree its at

Not understanding what your saying the pinion needs to be 0-3*?? Or are you saying they need to be at the same angle front and rear

Reference the pic (by XJlimitedx99 and upper of the two) that was posted, just so you have a visual so I can try to explain it a little better. You now have a SYE, this means that your u-joint angles now operate differently. You now want to angle your rear pinion to be as straight as possible (inline) with the driveshaft.

Yep, this right here. It also applied to your front driveshaft as well.

Roninofako stated 0-3 degrees because typically up to 3 degrees misalignment is acceptable and will not produce significant driveline vibrations.

Couple more points to make this even more complex than it needs to be:

1- You'll likely have people telling you that u-joints need some operating angle to provide proper lubrication, or something along those lines. They're correct. When force is applied to a u-joint that is operating perfectly inline (0 degree offset between input and output shafts), the needle bearings can indent into the cross, ruining the joint. This is called brinelling. I read a TSB from Ford which stated a minimum u-joint operating angle of 0.5 degrees.

2- On the rear end, the pinion angle you set while not moving is not the same angle that will be seen while operating at cruising speed. When you apply throttle, the pinion wants to rotate up. This is counteracted by the leaf springs, but the leaf springs will wrap, slightly. How much they wrap depends on many factors such as spring weight, suspension geometry, etc, etc, but the point is you'll never be able to get the angle perfect under all situations (without a traction bar). It may take some trial and error, but fortunately there is a fair amount of tolerance. Many people will say to set the pinion angle 1-2 degrees low to compensate for spring wrap.

3- Be aware that rotating the pinion on the front will also negatively affect your caster angle. These two angles are both very important and need to be balanced. You may hear of people "rotating their C's" on the axle to achieve desirable caster and pinion angle, but that's pretty involved and not required for most setups.

Another little something to consider is limiting suspension travel.

Setting up your pinion angles is fairly well laid out above so no additions to that point.

However lifting your jeep up and letting your axles droop on their own and spinning those driveshafts while you are in neutral can give you some hints to weather you are exceeding your driveshafts abilities or within operating angles. This seems like so.ething that's very often overlooked completely when getting into the bigger lifts and long arm setups. There is also limiting up travel with bump stops as well but prolly not a factor in driveshaft breakage

They need to be within 3* of each other, for example, if one side measures 27*, but the other side measures 32*, that's a difference of 5* between the two. A 4* shim at the leaf pack would make it 1* difference as opposed to a 5* difference. Capice?

NOTE: The numbers above are completely hypothetical. Just an example.

Things like this are why it's important to understand math, geometry, and physics. There's more to it than just buying parts and slapping them on.

It's better to understand what's happening when you lift your vehicle, and the effect of what you're doing to your rig...and, the more you modify one area, means you need to now compensate several other areas to make it work properly.

Modifying your Jeep is a science. So the more you understand about what you're doing, the closer you can get to a properly balanced ride. The goal is to get it as close to stock performance as possible. But after you jump into it, you'll never get it to stock performance.. close, but never the same.

Go into it knowing that, and you're going to be golden.

Ok I got it now thanks for the insight and support. I understand what i got to do now. Will let you know how it turns out.

Got it figured so but wanted to confirm. Caposh.