I really can not make out the angle on the 2nd pic...

 

it looks to me like its a bad angle. the transfer case yoke is angled down and the pumpkin yoke is pointed straight ahead.

 

When I had my vibrating and shaking problem do to my 3.5" lift on my 94 XJ it didn't start at 55MPH.. It was from when I started to move and just got worse as speed increased. SYE, Shims (6-degree) and a rear shaft fixed it. Yours starts at 55MPH. Sounds like wheel balancing to me.

 

that rear picture looks leik the shims mgiht of stupidly be put in back wards and i have 3.5 inch springs 2 inch shackles NO shims and my t case is pushed up further from a mod i had to do to fit the long arm crossmember and i have noooooo vibes at all its g2 be something else if 1 of ur end caps lost a bearring in the u joint it can casue that it happend on my work van and the vibes didnt get noticble untill about 45 so double check those

 

There isn't really any "backwards" to a shim. It all depends on the type of driveshaft and which way you have to adjust the pinion angle. For example, on my '99 XJ I used OME 2.5" leafs and a set of JKS shackles. With no TC drop, I measured the rear output shaft angle at 4 degrees down, the driveshaft slope at 14 degrees and the pinion yoke at 8 degrees up. This caused a very bad vibration and "tinking" noise starting at 5 mph. I added 4 degree shims, tapering to the rear, to correct the pinion angle back to 4 degrees up. No more vibe or noise. Most assume the shim goes in with the taper to the front, but it depends on which way you need to adjust the angle.
If I was using a CV type driveshaft then I would measure the driveshaft slope angle and set the pinion angle one or two degrees less than that. In my case above, that would mean spinning the shim around to add 4 more degrees to the pinion angle instead of reducing it.

 

thats what i ment lol thanx for understanding it and putting it into words that other can understand about backwards i ment wrong way haha

 

I did the Iron Rock hack n tap SYE. Pretty easy to do. I took my front driveshaft and put it in back and mine still vibrates. I think i need new u-joints.

 

agreed the shaft angle pictured are not causing a vibe either tires or balance prob unless ds out of balance

 

Could your drive shaft possibly be bent?

 

Ok, The U joints are new and I also am using a DS out of a parts Jeep that drove fine so it is balanced. The diff angle was way off before I added the 2degree shims. I have run two different sets of balanced wheels and it vibes with both of them but a little bit more with the cragers than my mickey thompson aluminum wheels. I am now thinking it might be my track bar heim joint has a little play and that might be causing the vibe/shake at speed.

 

Bump.. Would the track bar heim cause the shake/vibe at speed? Its a RE bar and it has a little play not crazy. I would replace the joint but it won't un-thread from the bar.

 

I would try removing the transfer case drop and shims, my 98 has nothing but a 3.5" rear lift and i have almost unnoticeable vibes at 25-30mph and thats it

 

X2 on this also, an unbalanced or bent driveshaft can really shake things up

 

Did you ever try the wheel balancing. Problem usually starts around 50/55mph and gets better after 75/80.