After installing my lift a little more than a week ago, I measured my driveline angles. The lift is an RE 3.5" SR with full springs. As noted in the drawing, the output shaft and the pinion shaft are within 1 degree of each other, while the shaft angle is 16 degrees. I understand that an SYE is in order, but my vibes aren't bad enough to get in a hurry. Can anybody tell me how this compares to their non SYE angles? I'm not trying to solve a problem here,,, just curious.

 

What year is your XJ? In 1999 or 2000 they switched to a lower front pinon "TJ style" D30. When you lift these models they are more prone to vibes than earlier models due to the increased angle on the front DL. Prior to that the XJs had a high pinon D30 in them. If you are experiencing vibes it might be from the front driveline. At 3.5" you really don't have to put a SYE in it. And if it is the front, a SYE will not help. Personally I have 6.5" with a T-case drop kit and no SYE and I don't have any vibes in my drivelines. Hope this helps!! Good luck!!!

 

This is a 98. My vibes are faint but I know they are their. I do have a 2.5º shim set that I'm going to try out. Won't take and hour. Thanks for the info.

 

A T-case drop will reduce all of your angles at the same time and it's cheap and easy!

 

I disagree...It reduces the rear driveshaft angle while increasing the front driveshaft angle. Transfercase drops are just band-aids for the problems of vibrations in a Jeep's power conversion. The multitude of variables are too great to try and fix with a t/c drop. A SYE kit is a more permanent solution and places no additional stress upon the front driveline. Just my opinion. Do as you wish, but a t/c drop is a stop gap measure.

 

A TC drop increase the front drive line angle??? How, mine looks better now that I put one on. Also a TC drop can be bought or made for 20 bucks compared to a couple hundred when taking about SYE's. I always like the TC drop solution when your own a budget.

 

From the way I see it, when you drop the case, you are tilting the drivetrain. The rear output is brought down some but as you do this, the front output is being lowered AND pointed up just a bit. That can increase your angles some. Think of a straight line. Lower one end and the opposite end points up more. Same thing applies to the t-case.

A t-case drop mainly buys you time to do it right, which is the sye setup. It's ok for a while but not a permanent solution. When it comes to an xj, the sye is a wise choice. say you bust ur rear cv driveshaft out on the trail. You have no spare so you can take the front off and put it in the rear this is good if you run a front locker cuz you can't drive on the street in FWD with a locker.

 

...also takes away groudn clearance ang most possibilties for t-case skids. t-case's are vulnerable enough, the last thing you want is to make it stick out further to the rocks... SYEs with tom woods shafts are also a significantly stronger setup.

 

Not to mention a transfer case skid to protect the delicate aluminum case from those dastardly rocks.

 

Thanks for the input everyone.

I did drop the TC when I put in the lift. Thanks to the guy who lost the bar that keeps an outboard boat motor in place while travelling. It's one inch square tubing. Cost - 0, except for carrying it from the front yard to the garage, oh, my back hurts.

Anyways, I put in the 2.5 degree shims. Made it worse so out they came. I'm satified untilo I get the SYE kit.