front driveshaft vibes

[A_J]

Possible Dumb Question Alert:::::::

90 XJ, 3.5 inch lift, np 242, SYE, TW rear shaft, 4 deg shims on the rear

I have some vibes that I'm sure are coming from the front shaft (I took off the shaft and the vibes went away) now I want to know what to do next.

After the lift and SYE I had to shim the rear axle to stop the rear driveline vibes. Could the font shaft be having the same issue? I didn't shim it b/c I hadn't read anywhere that I needed to, but I'm thinking that might be the problem.

The shaft is off the jeep now b/c I am replacing the u-joints just to rule that out, so I don't have the angles on the front. It *looked* ok, but I didn't measure so I'm not 100% sure.

So I guess I have two questions:
1) Has anyone had to shim the front axle after a similar lift (3.5")?
2) Am I doing any damage to the front diff by running without the front shaft in place? I don't plan to leave it for more than a couple of days, but I want to be sure I'm not screwing anything up.

thanks in advance for the help.

[luvdaxj]

You won't do any damage by not having the front driveshaft in. I've never heard of shimming the front axle. How bad were the U-joints? That could be your problem.

[A_J]

U-joints were pretty good actually, so that's why I think the shims may be needed. The CV joint U's looked like they hadn't been lubed in a while, but otherwise ok, so I'm not going to replace them just lube them up.