RaleighXJ

Hey ya'll,

Lots of great info out here hoping for some advice.

This is my third xj, the other two were just stock (88 and 89) rode hard put up wet beasts that I did nothing to other than basic maintenance to keep them on the road.

This new add to the fleet is my first 97+, bit of a cream puff I came across on a song so I decided to put a little money into it, lift it with tires, and bounce it around in the desert.

Thing handled and ran great before the lift, now shudders at take off almost like a bad u-joint. if i accelerate fast its only a split second but slow take off kinda "thud thud thud" like smething is out of balance. Lasts just a few rpms then runs fine. ujoint ain't the problem from what I can tell, can't get any play out of them when she's parked. Only happens at take off, some shuddering at like 60 but I'm chalking that up to the lift and tires with a shot stabilizer (on the to do list).

3" pro comp coils/leafs, trac bar relo, links, longer arms, tc drop. Popped the lids on both diffs (did the front cuz I bought a gallon of gear lube and evidently needed to blow $5 on a gasket so why not). Dana (35?) front chrys 8.25 rear, not a lick of metal in either. I know the jeep was maintained as it was a fleet vehicle for a company, all svc records, all highway miles.

So I've checked both ends of the problem, scurd to work towards the middle. Have swapped a 242 on another jeep before no biggie, but not sure that's even my problem. tranny fluid looks fine and it shifts fine. given only 120k on this xj I would prefer fixing than swapping with a 190k tc or tranny but hoping I'm missing something more obvious and less complex.....or expensive.

Is an SYE install common/necessary on only 3"? Could that be the issue? What does the SYE "solve"? Torque converter? No hitch or hitch remains so it wasn't a tow vehicle.

Contemplating taking out the tc drop to see if it makes it better or worse then working backwards from that.

Any other thoughts? Much obliged for the help.

Donnie_K

Did you get it aligned?

RaleighXJ

Yes, aligned

98XJ40K

I put a TC drop on my 98 with ~3.5" lift and got rid of the vibes. I have an sye going in shortly. They say that it is hit or miss on driveline vibes on the 97+.

77olds

Your u-joints on the rear drive shaft are binding because they're at too much of an angle.

Yes, you DO need a SYE or at LEAST a 1" t-case drop for a 3" lift.

I had the very same problem, spaced the cross member with 1" square tube and the problem went away.

RaleighXJ

Tc has been dropped 1", don't suppose I can go any further? I imagine at some point that's no good for alignment off the motor. I may replace that ujoint anyway in case it's dry or otherwise effed inside and see if that helps. The ujoints are super rusted outside, no slop like I said but could be getting there

It's def a post-lift issue, doesn't feel directly connected to the tc (when I hold the 4x4 lever at take off it transfers the brief wobble some but doesn't feel "right there") but something is maxed on the driveline, ujoints are cheap enough...

Will have the wife drive it and maybe hang on to the bumper while riding the creeper see if I can narrow it down

Will post results, appreciate that and any other feedback

salad

No. TC drops are a bandaid stupid idea anyway that rob you of ground clearance (from that lift) and put a lot more strain on motor and transmission mounts.

Pull the rear DS and drive around a bit. I suspect your rear U joints are binding.

helmut

leaf shims

RaleighXJ

Replaced both rear shaft joints, still shudders.

The more I think about the 1" t-case drop I installed the more I wanna remove it and do it right.

I hate bad vibes, especially on cars. I know this is minor but this thing had no wobbles, shudders or shakes when I bought it and I'm determined to keep it that way, realizing SOME extra noise is the cost of off road capability.

Suppose ill shift gears and start researching SYE with shims, off to another forum search, appreciate any tips as I head that route.

Some pics of my XJ, list of wants goes on and on but off to a good start.


Before




After

Tom95YJ

When I worked at 4WP this was a common problem we hear plenty of feedback about Degree Shims would fix the issue 90% of the time