Can you run a 3.5 in Pro comp lift on stock control arms without any caster or Pinion issues?

Kaptainkid1

Kaptainkid1

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I have a used TJ that was modified by the last owner. It had a pro comp 3.5 in lift. The following was done on the lift: springs, shocks, 1.5 transmission skid plate drop, a stock rear end drive shaft, front & rear sway bar drop and Geometry Correction Bracket Kit. Running on 31 10.5 r15.
Since I didn't install the lift, will any these mods effect the caster or pinion using stock control arms? I have since replaced the lower and upper control arms but kept the same length as a reference point.
I'm going to try to adjust my suspension this weekend and make sure my caster and pinion is adjusted correctly.
Anyone know any video or links to adjust these points? I have upper adjustable control arms and fixed lower control arms.

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First, I don't believe ProComp ever made a 3.5" lift for the Wrangler TJ. 2" and 4" is all I recall and I worked for their parent company in a previous life.

And yes you can run factory length control arms with a 4" suspension lift but it's a terrible idea for the below reason.

Assuming it's a 4" lift since that 1.5" transfer case drop is there, I'd worry less about caster and pinion angles and worry more about installing a slip-yoke eliminator (aka SYE) kit into the transfer case and installing a double-cardan (aka DC) driveshaft. Companies like https://4xshaft.com/collections/slip-yoke-eliminators/products/np231-slip-yoke-eliminator have kits for the TJ containing both. Unfortunately they're sold out of the SYE kit but they're easily found elsewhere. I just put that link there so you can see it.

That will allow the drivetrain angle's to be running correctly to allow the eliminate that terrible 1.5" tcase drop which gives you the ground clearance equivalent to a 2.5" suspension lift.

The adjustable length control arms you asked about are needed for the SYE and DC driveshaft since they will allow the rear axle's pinion angle to be properly changed to match the requirement of the DC driveshaft. Basically the DC driveshaft requires the rear axle's pinion angle to be raised so it's at the same angle as the driveshaft.

Do you have the budget to install the SYE kit and DC driveshaft? That combination is really considered required for such a tall (4") suspension lift. That 1.5" transfer case drop was a terrible band-aid approach to eliminating the drivetrain vibrations caused by such a tall lift.
 
Jerry Bransford said:
First, I don't believe ProComp ever made a 3.5" lift for the Wrangler TJ. 2" and 4" is all I recall and I worked for their parent company in a previous life.

And yes you can run factory length control arms with a 4" suspension lift but it's a terrible idea for the below reason.

Assuming it's a 4" lift since that 1.5" transfer case drop is there, I'd worry less about caster and pinion angles and worry more about installing a slip-yoke eliminator (aka SYE) kit into the transfer case and installing a double-cardan (aka DC) driveshaft. Companies like https://4xshaft.com/collections/slip-yoke-eliminators/products/np231-slip-yoke-eliminator have kits for the TJ containing both. Unfortunately they're sold out of the SYE kit but they're easily found elsewhere. I just put that link there so you can see it.

That will allow the drivetrain angle's to be running correctly to allow the eliminate that terrible 1.5" tcase drop which gives you the ground clearance equivalent to a 2.5" suspension lift.

The adjustable length control arms you asked about are needed for the SYE and DC driveshaft since they will allow the rear axle's pinion angle to be properly changed to match the requirement of the DC driveshaft. Basically the DC driveshaft requires the rear axle's pinion angle to be raised so it's at the same angle as the driveshaft.

Do you have the budget to install the SYE kit and DC driveshaft? That combination is really considered required for such a tall (4") suspension lift. That 1.5" transfer case drop was a terrible band-aid approach to eliminating the drivetrain vibrations caused by such a tall lift.
Click to expand...
I'm going to do the SYE next when I save enough for that mod. I'm guessing next 6 months. I will then pull off the 1.5 inch Tranny spacer off. It's not a big deal as of yet since I don't have any drive line vibration.
 
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