Hey Guys,

Question for the mechanically inclined

If you have a 3-4 inch lift with all adjustable control arms and STOCK rear driveshaft is it typical that that the rear diff still needs to be rotated to get a decent pinion angle? This is on a 2012 JKU.

Thanks!

 

Mine is still just slightly off with no issues with a stock shaft. When I go aftermarket it will get it perfectly lined up.

 

First off, an after market shaft should be angles about 1-2 degrees down from level.

Second, the stock driveshaft uses an rzeppa joint, which is designed to operate at an angle. The pinion angle should be at the same angle as the transfer case output. Running it straight will cause premature wear and failure.

 

What he said.

The stock rear joints are true CV. Angle has no bearing on vibration. Extreme angles (greater than 7 degrees) can cause excessive wear and so can zero angle. The reason Jeep uses them on the rear and not the front is because you don't drive fast in FWD so minimal load on the front DS on highway. For full-time 4WD Jeep would have needed CVs on both ends of front DS too.

 

So if you have fully adjustable control arms is there any advantage to an after market shaft?

 

Advantages of an after market shaft:
- U-Joints are repairable on the trail (if you have spare parts).
- Less rubbing problems,
- Less likely to be damaged rock climbing.

Advantages of factory shaft:
- Less vibration at high speed (until you dent or bend it on a rock).
- You already own it.
- Pinion angle not critical so gear oil level sets differential (pinion) angle for optimum lubrication.