Perryrich850569

PatHenry

It could be a bad axle u-joint, could be a frozen/stuck brake caliper, could be a bad hub bearing. You will have to dig into it and see what's going on to know for sure.

I'd jack up the passenger side and remove the tire. If you see a ton of brake dust and have excessive wear on the pads/rotor, I'd suspect the caliper is frozen. If the brakes look good I'd spin the wheel and see if it spins smoothly. If it is rough or noisy then I'd suspect a bad hub bearing. You can get a good look at the axle u-joint as well, if the u-joint is not tight, then it needs to be replaced. (The u-joint is probably the easiest to confirm visibly if it's really bad.)

You could have one or more of these possible problems, but they're pretty easy and not super expensive to fix.

Let us know what you find!

caged

not all bad u-joints are sloppy, some seize up.
from what you described, i would lean towards axle u-joint.

but to know for sure, you will need to jack up the jeep, grab the tire and wiggle to see if there is play there in the hub. if it feels good, give it a spin.
then remove wheel and inspect brakes. spin the rotor and see if it's rubbing on the brake pads. if it's good, then start removing the caliper and rotor.
you will then need to pull the 3 hub bolts and remove the axle.

once the axle is out, you should be able to tell if the joint is stiff or seized. it may also be sloppy.
there is a way you can tell if it's sloppy before even jacking up the jeep. you just need to get under it and grab each side of the joint and twist each side opposite of each other. but it can be tricky if it's your first time. and it won't tell you if it's seized. best way to know for sure is to remove it.

Perryrich850569

PatHenry

Is that mud on everything? (Sorry, I'm color deficient)
If so, is that from recent wheeling?

The reason I'm asking is that I don't see anything obvious from the pic that screams "bad u-joint". I'm not an expert by any means though and certainly a 20 year old u-joint is likely in need of replacement.
However, if you're getting a lot of dirt build-up in that area it could be a sign of fluid leakage (usually either brake fluid or gear oil in that area.)

If you're definitely going to do the u-joint, you'll have the brakes and hub apart anyway, so you can get a good look at them and determine at that time if you want to replace stuff.

Do try the "shake the wheel" thing to see if there is play. A bad u-joint won't show up as wheel play side to side or top to bottom.

Another thing to consider is ball joints. Definitely see if they're in good shape since if you have the axle shaft out it would be an opportune time to do the Ball joints if necessary.

PatHenry

Just a personal thought - if you're doing one side u-joint, I would strongly consider doing the other side too if both are original.

Obviously this isn't required, but if you're going to get dirty and have your tools in your hand, you might as well go all the way.

Perryrich850569

PatHenry

Hahaha, no worries. What is a "strip job"? I'm imagining mining of some kind.

I'll take your word for it that it's bad since I can't see red very well.

I think that as far as your original question the advice provided is very good. I think you probably have at least 1 other problem due to the vibration at high speed - so probably one of the other things is also going on.