Hey All,

I'm at 4.5 inches of lift on 33s. Have 4.56 gears and a transfer case drop. I had slight vibrations even with a transfer case drop. Could not having a sye cause my driveshaft to have snapped? Driveshaft u joints were less than a year old and only had about 2k or 2.5k miles on them.

 

I'm also at 4.5 and I had to add in a sye to get rid of Driveshaft vibrations and yes it could snapped the u joint because it will vibrate when the angel is to much .

 

If you haven't touched that pinion yoke, then the cause of your problem is that the U joint strap bolts are loose. So bottom line is the joint moved to one side and caused failure. Also, you will need to replace the straps and bolts, recommended by Chrysler and Dana when changing U joints. You don't say what year your Jeep is, but the style of tcase tail housing says 96 and up to me. The issue for these is that the yoke gets moved too far out on the shaft and wobbles. Ultimately I think you will need to go with an SYE to get it right

 

First of all, thanks for the detailed response. I do most of the work on my vehicle, but I don't do a few things that are beyond me. Like a regear. I believe the guy who did my regear did a good job. It is possible the straps worked themselves loose enough to cause issues. But who knows what exactly happened. Instead of replacing the u joint on that driveshaft, I believe I'll get a sye kit and ditch the transfer case drop.

This is a 1996 XJ btw. You were right on the money there.

Do you have lift and an sye on yours?

 

Hey OP - man, I hate to see that because one month ago I was by the side of the highway with the SAME issue. I had just gotten my first XJ, on a 6.5" lift and 35s, and the POs had cut every corner they could, so no SYE. When it first started I thought I was on a rumblestrip, but realized I wasn't, and then the rear driveshaft was banging around everywhere underneath the jeep until I pushed the clutch in and pulled over. 5 seconds total. I had to get the GF to bring me a hand sledge that took me 20 MINUTES to bang out the rear DS with so I could put it in 4hi and get home. The transfer case was all buggered and it even broke the front housing, so I rebuilt it.

I'm no expert but from all the research I did I would think that at 4.5" you would really need an SYE to prevent this again and just make everything work better. The bolts on the u joints are pretty small and even if they got some locktite they can only be expected to endure so much vibration before they give it up. The SYE really wasn't that bad to install myself, and I've heard you could even do it without pulling the TC. Lots of good YouTubes on it. I tried to order a JB Conversions SYE but they are out of stock and they wouldn't return my call to see when it would be in, so I got an Advance Adapters one, doesn't really matter. Anyway, I'd say go for it to have a stronger jeep and more peace of mind.

 

You could say that. I have an 8" lift. But instead of an SYE, I have an Atlas 4 speed, so that eliminated the slip yoke anyway and I have the double cardan type driveline that you would have with an SYE. The thing with straps is that they stretch. I have spit a few drivelines out with them, so that is why I am now converting to U bolt type yokes now myself.