Ok, I am fairly new to working on cars, no one else in the family does, and I was wondering about driveline angles. I am installing a 4.5" RE Extreme Duty Lift kit, and also a JB Conversion Slip yoke eliminator kit on an '89 YJ, and was wondering if there was anything else I needed to install to fix the drive line angle....
You might need to consider a transfer case drop also. They don't consist of much, just some spacers to drop the rear crossmember down about 1 inch. You might have to change your pinion angle on your front and rear axle, depending on what type of rear driveshaft you use with the slip yolk kit. Steve
The yokes must be within 3 degrees (0 being best) of each other. Think parallel.
The drive shaft (down) angle from rear axle to transfer case yoke should not exceed 13 degrees. If either the 3 degrees or 13 degrees are exceeded you need to use a CV style rear driveshaft with the differential yoke aimed 1-2 degrees below the transfer case yoke center.
DON'T change the pinion angle on the front. If you do it drasticly changes your camber and your jeep will have many handling problems. It's better to live with the minor difference in the front since it is only used in 4wd. Install the kit and check your pinion and t-case angles. Set the rear 1 degree lower if you run a hardtp that sn't on when you do it. You can buy shims with different degreess of angls that go betwean the axle pad and the spring. The kit will probably come with shims that get it pretty close.