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rear pinion angle question

bluebomber

NAXJA Forum User
Location
Republic, WA
i have searched this already and come up with conflicting info. i have a 2001 xj with RE 4.5", AA sye, and TW ds. the ds angle shows 21* and pinion is at 17*. after searching the other threads, some say to set pinion angle 1* below to compensate for axle wrap and some say 2* below. which one would be correct?? i'd like to buy shims that will correct the humming on acceleration problem once.
 
i have searched this already and come up with conflicting info. i have a 2001 xj with RE 4.5", AA sye, and TW ds. the ds angle shows 21* and pinion is at 17*. after searching the other threads, some say to set pinion angle 1* below to compensate for axle wrap and some say 2* below. which one would be correct?? i'd like to buy shims that will correct the humming on acceleration problem once.

Tom Wood's recommendations for driveshaft angles.
http://www.4xshaft.com/index.html

If driveshaft wrap is causing problems, you need to control it.
 
if you are having bad axle wrap you need to stiffen up your rear or a ladder bar...
you should be fine within 2.5* of the pinion angle. i was having some axle wrap and threw in some stock leafs to help, my pinion is now about 2* below, maybe 2.5*. anyway i have no vibes related to pinion angle.
so if youre 4 under i wouldnt go any more than a 3* shim.
id prob do 2* shim. use only steel...
anyway you also could use a longer shackle, that will also point the pinion up a bit, like from my experience anywhere from 1-3* between a 1.5-3/8" lift shackle, ive ran commanche shackles, rough country 1.5" and 1" and always measured and they definetly move the pinion upward a bit. in your case id say 1".
also cheaper and easier than good metal shims, the two sets of metal shims i bought were around 50$ shipped...
 
Pointing the pinion down slightly isn't because of bad axle wrap, it's to account for a slight (couple of degree) raise in the pinion when power is applied to accelerate or maintain higher speed. 1-2* is usually good, the only perfect setting is the one that doesn't give you any vibes.
 
thanks guys for the input. i had a buddy help me with checking the pinion under load while watching it. there wasn't much axle wrap as i thpught. it just needs to be pointed up a few *'s. i was kinda stumped on whether to go with a 2* or 3* shim. i think 3* would put it at just under and allow for some upward pinion movement to get the right alignment.

thanks again....
 
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