I finally got this running and going like it used to. It's a '96 with 162k and really no problems. I have put a lot into it. Thursday I was in town driving and noticed at 35 plus it started to vibrate. I once bought New Falken tires that were eggs. The jeep was not easy to drive with the vibrations, about two months later they were stolen. Today, I started and heard something that sounded like rubbing and then almost like the brakes were down to metal. I have had this for 16 years and have just about replaced everything you could i.e. ball joints, steering, track bar, shocks, coils, leafs, tires a few times, trans and drive shaft. It has a 4.5" lift with 33's. Front and rear brakes have plenty left on them. I have checked for loose wheels but they are tight, I have not taken them off to check for anything loose behind them. My fenders are cut so they don't rub. The wheel bearings are original, I think. I have new ones but how would I tell if the current ones are bad. Other than the wheel bearings, it might be a bad u-joint in the axles or drive shaft I don't have a go pro to attach while I am driving.

 

There is a lot on a lifted jeep to make noise. Step 1 are your primary drive shaft u joints , that means front / back/ left and right..grease able or still factory sealed...the life of a sealed joint is about 150K give or take. The front axle shaft ujoints will make more noise in a turn than straight. Jack the front end or use jack stands and give the wheels a strong shake in every direction. Does any ball joint or tie rod end move? 4 1/2 is a lot of lift...SYE, or tcase drop...did you extend your rear tcase yoke? Bad front wheel bearings usually make a thumping noise, usually also in a turn. Have you made any recent changes , when you cut fenders, what happens to the plastic wheel well covers, my fronts sometimes pop out of their slots and the wheel hits in a turn

 

Mine didn't have plastic in the wheel wells or if it did, they were either gone when I got it or I removed them when cutting the fenders. I cut those fenders when I first got it back in 2009. I have greased the zerts on the greaseable u-joints but will check again. The front steering got greased up as well. I do not have an SYE or drop, but my issues aren't from that as I have always had a lift and the vibrations haven't come from that... I don't think. I know this can be an issue and it's in the works to get done. But this vibration is new and not a clunking sound from making a turn. This sound and feeling (my rear view mirror vibrates when the sound gets louder, just like the 4 new Falkens I bought in my previous message) gets louder and more progressive as I drive over 35 to 40 mph going straight.

 

I jacked it up and found that the wheels have play from side to side not top to bottom. While it was up, the front drive shaft yoke seemed loose but when I had the back jacked up the rear one did too, back on the ground they are not loose.

 

Its tough to identify something exactly if your not there...rotate tires, and test. Check Diffs and xfer case for proper oil level. Jack up back and front and give both driveshafts a good workout. Check for excessive brown dust on the crosses, look for any motion in them while spinning , rotate shaft back and forth quickly looking for play and listen for any noise. I thought you mentioned a metallic sound...luckily even bad tires don't sound metally

 

I have mostly done all that you said, especially when I had DW. I guess since it happened all of a sudden, it made me think what now. I know its a '96 and almost 30 years old. I keep it in tune with how I drive and do regular maintenance. I recently replaced the steering box and pump. I have changed about every sensor and replaced the old with the new. You could say that I am in the process of restoring it in slow motion. Maybe some day I will finish it amongst all my other projects.

 

side to side play in wheels is a tie rod end loose...just played that game 2 weeks ago. It was the rod end above steering stabilizer

 

It might be moot now but check your motor mounts and tranny mount...Have someone rev engine in gear with brakes/parking brake and chocks while watching for motor movement..once had a blown stock mount and oil filter would rest on frame causing vibration

 

So I took it in the get the wheels balanced and rotated and yesterday I checked the fluids in the diff's. The front needed a tiny bit and the back was fine. After the rotation I left for a few errands and to get onto the freeway for a few miles. I am noticing that from a dead stop and I get on it, it vibrates. When I am going under 45 it seems fine, but when I got on the freeway I noticed it vibrate a bunch. I am thinking it's the rear axle yoke possibly. I am going to pull the rear axle and run the front and see what happens.

 

What yoke are you refusing to? The slip yoke possibly? Slip yokes do wear out and will allow your drive shaft to whip, causing vibration. You might want to remove your drive shaft and inspect the slip yoke for play.

I had similar vibration and it turned out my front drive shaft slip yoke was worn out. New shaft fixed it.