front driveshaft angles...

for years had an RE 4.5" lift, nonadjust. upper and lower control arms.

a little bit of shimming with an sye perfected the rear driveshaft, but I've always had somewhat noticable vibes up front, nothing to alarm me. Also don't use 4wd all too often so was never an issue.

now that i think about, and reading a recent thread, i'm thinking about how one goes about perfecting the pinion angle up front. I should add that I have a set of RE drop brackets and braces I someday plan to install.

Again, it's more of a "mild rumble" that lets me know i'm in 4wd, but how would one reconcile pinion/drive shaft relationship to smooth that out, if indeed it even needs to be?

Thanks...

Vacuum disconnected front axle or not?

if not the driveshaft up front will be spinning 24/7, regardless of if you are in 2wd or 4wd....

'98 non-disco, funny, just rebuilt axle including cv joint,vibes seem a bit less than before, still kow it though when in 4wd...

Hm, it wouldn't make sense to only notice a vibe when power is on the driveshaft....or would it?

First, I'd recommend that you install the drop bracket kit. Your ride will be much better and you won't wear out the control arm bushings near as fast.

It makes no difference whether you're in 4WD or not. The vibes are most likely the result of the pinion angle. You can use adjustable LCAs or adjustable UCAs (or both) to correct the pinion angle or dial in the caster. Most here say proper pinion angle overrides caster. With proper pinion angle the U-joint will operate as it's intended and last much longer, and the front vibes should cease. However, it's at the cost of less than idea steering.

You can also shim the LCAs with the drop bracket kit. This might help some and is an alternative if you can't afford adjustable control arms now.

no vibes whatsoever when not in 4wd, sorry, didn't clarify that...