Driveline angles mixed answers (have searched)

So after searching for the correct angles to have in the driveline for the stock 2 joint xj shaft i have found alot of mixed answers. I was always under the impression that the angles from the transfer case output to the pinion needed to be parallel. I was going to shim my pinion angle down because it is too high and i have read answers ranging from parallel all the way to 3 degrees below that of the tC output. I was planning doing a happy medium and drop it a degree down to compensate for the pressure put on the rear that causes it to rise when accelerating. I was just wanting opinions from people who have done this or just know whats best.

Thank you

need some more info. what year? is your rig lifted? if yes, is it leafs, a shackle etc? oh and pictures always help.

Its a 1996 lifted 2" coils in front 2" shackles in rear. I measured the angles and the pinion needs to drop about 3 degrees to be parallel with the tc output. i was just going to get 4 degree shims which would put the pinion one degree below, which seems like the best thing to do IMO.

Branmuff09 said:

Its a 1996 lifted 2" coils in front 2" shackles in rear. I measured the angles and the pinion needs to drop about 3 degrees to be parallel with the tc output. i was just going to get 4 degree shims which would put the pinion one degree below, which seems like the best thing to do IMO.

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That sounds correct. Heres some good info to, http://www.4xshaft.com/

thank you very much!

For stock drivelines with one u-joint on each end you want them to be parrallel. If it's double-cardan(ie fron driveshaft in rear) you want the pinion to point at your t-case output.

Alright thanks! only reason i thought the rear pinion should be 1 to 2 degrees lower was because i heard that because xj's have leaf suspension in the rear the angle will even out when you are driving due to axle wrap.

You are correct in assuming you need to have the rear pinion ~1 to 1.5 degrees below the TC angle. Leaf sprung rears, especially with spring packs located on the top of the axle (Jeep XJ), will exhibit spring wrap even at steady highway speeds. This must be allowed for by adjusting the rear diff pinion angle down with respect to the TC output shaft angle. The problem is projecting just how much wrap you will experience with a given set-up; lifts using blocks in the rear, and softer leaf packs mean more spring wrap, which implies more negative adjustment. The problem is exacerbated by shim availability, and the fact that a measured 4* shaft angle will not change 4* when a 4* shim is inserted; so it becomes an iterative process to get to the right angles.

alrigh thank you! i figured i'd have some adjusting to do but for now ill start out by making it a degree lower, then ill just work from there if it doesnt fix the problem.

How far below parallel it should be depends on how floppy your leafs are (heavy duty lift springs should be closer to parallel than stock leafs, etc) as well as how hard you are on the throttle. Basically you just want it to be parallel when you are on the gas.

A degree or two below should be fine.

Hello,

Ideally the tc and pinion should be //.
So the two joints have the same angle and cancel each other out.

However after saying that, IF :

The angle of each joint exceeds the working angle of the joint all bets are off.

On a cardan joint ( Double jointed CV style ) the pinion should be 2 degrees down from the shaft at the rear and the cardan will be whatever at the tc.

Again: Unless you exceed the working angles of the joints ( at the cardan side ).

This is where the length of the shaft becomes inportant, the longer the shaft the less severe the angles.

You really need to know your lengths, angles, and joints specs to solve all the issues.

Hope this helps.

Nitro