How do I change my pinion angle with adjustable control arms?

DropTopDon

DropTopDon

TJ Enthusiast
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My brother recently bought me a pair of MC rear upper adjustable control arms. I have seen that a benefit of rear upper CA is that you can correct your driveline angle if you do not have a double cardan driveshaft, which I do not. I have 3.75 inch of lift in total so I think it would be pretty beneficial to me to correct my angle. Forgive me if this is a rookie question but how would I go about changing the angle of my axle while I install the control arms? Would I install the control arms to the exact length as the OEM ones and then adjust them once they are on until the rear driveshaft appears to be in line with the rear axle? Thank you in advance.
 
Depends if you have single or double adjustable arms. For single it is easier to support the pinion with a jack, remove both arms, adjust the pinion with the jack and then install the arms adjusting them to fit. Double adjustable allow you to install them at stock length and then adjust them after they are installed.
 
Haaris Khan said:
My brother recently bought me a pair of MC rear upper adjustable control arms. I have seen that a benefit of rear upper CA is that you can correct your driveline angle if you do not have a double cardan driveshaft, which I do not. I have 3.75 inch of lift in total so I think it would be pretty beneficial to me to correct my angle. Forgive me if this is a rookie question but how would I go about changing the angle of my axle while I install the control arms? Would I install the control arms to the exact length as the OEM ones and then adjust them once they are on until the rear driveshaft appears to be in line with the rear axle? Thank you in advance.
Click to expand...
Since you do not have a DC driveshaft, set the uppers exactly the same length as the stock uppers, remove one and install the MC in its place, then remove the other and install the MC in its place. Do not remove both of them at the same time and then start putting the MC's on. You do not need to change the angle. You need to keep the geometry like the bottom pic in this diagram. No need to adjust.

However, you must have driveline vibes with 3.75" of lift and no DC driveshaft (if you do not have a rather large TCase drop). Thus, what you really need to do is get a DC and the proper driveshaft. Then you can start adjusting the upper CA's so your pinion looks like the upper pic in the diagram. Lifting the pinion with a jack helps if you have single adjustable arms.

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Keep in mind, the transfer case output and pinion will not necessarily be flat and parallel to the ground, as they appear in the lower picture. Since they should be parallel to each other, adjustable CAs may help achieve this and reduce vibrations; even if you don't have a DC shaft.
 
TJs are famous for thwarting workaround solutions. Bite the bullet, get a SYE, a nice Tom Woods drive shaft and install an actual cure. Lifts are for adding ground clearance and dropped transfer cases are a method that works in the wrong direction. Your rig is going to extract a tithe from your wallet anyway so face it like a man and give give give.
 
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With that much life a SYE is almost always needed to keep vibes away. Or drop the transfer so much that you are loosing the purpose of having a lift. And to really get your pinion angle and axle location right you should really have adjustable uppers and adjustable lowers too.
 
My PO installed a 4" procomp lift with enough of a TC drop to make it pop out of 2nd all the time (and probably 4th, but I never use 4th with 3.73s on 33s.) All of this is currently being undone.
 
Correct me if I am wrong, but one should be able to feel their driveline vibrating while they are driving. I have a one inch MML but I don’t think that alone would eliminate my vibes if I had any. I do not have any driveline vibrations even without a tc drop or SYE. I still plan on purchasing a SYE along with a TW driveshaft but I’m still a teenager so gathering money for my parts takes me some time.
 
Gathering money takes time, for everybody but I understand. Too bad you aren't in Florida. I can't find a teenager that will work anywhere. A few weeks of work would fund the whole project and leave you money left over for gas.
 
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