Alright, I started noticing a harmonic vibration after I have 4.56 gears installed. I figured everything in the driveline is spinning faster and so I didn't notice it before because it never had to spin this fast. So I rebuilt both driveshafts, a little better, swapped front driveshaft with spare I had in the garage, a good bit better, took out rear driveshaft and drove with front, maybe better but not a really noticeable change, rebuilt transfercase and 2 new driveshafts, just rear in there's a little vib not bad, both in wasn't too much worse yesterday, got on the highway today and anything over 50 was vibrating really bad. So in total: Hub bearings ~1 year old Axles bearings, seals, and gears ~3 months I think Driveshafts and transfercase rebuild last couple weekends. This is driving me crazy. The pinion angles look good, but may try removing the rear shims. I need to get this figured out because it's my daily driver and it's fairly important I can take it on the highway.

Edit: I messed up originally. I've had the vibration but it wasn't noticeable till like 90+ and was barely noticeable then, but now it's noticeable at lower speeds.

 

I would start with checking the tires and wheels to eliminate those as a problem first, being you had it before doing a gear change.

 

had them balanced last weekend or the one before. Definitely made a difference, but I figured it was in the driveline since it started showing up at lower speeds after the gear install.

 

I would check the pinion angles again front and rear, check the rear shims that they are correct for your lift? They had to play with mine a couple of times to get them right after I increased the lift and installed the SYE. The upper CA's had to be adj. more as well, I might add that my gears and lockers were installed at the same time as well.


I made a lot of changes from the 3" lift I started with and replaced many parts steering as well so planned on a few issues to begin with but they corrected them all before I left the next day.

 

my next idea was to remove the shims even though the angle looks almost dead on, a hair low since I have leaf springs to let it rotate some but I'll check both and I have a couple guys from the Clemson offroad club looking at it when they get time.

 

I had to use shims with mine but all are different. It's hard to find a problem online like this one and your lucky to have someone with experience to help having a look at it.


Please let us know what ended up being the issue.

 

Have the gears gone through the proper break-in procedure? Oil collected in clean container and gear mesh inspected?

 

If I was you. I would put the jeep on jack stands. Take the tires off, and rear drums. Take out the front shaft leave the rear on. Get in and take it up to 45-55mph. If no vibes take out rear shaft put back in the front and do it again. If no vibes now take out front again, replace the rear shaft. Now this time put drums and tires back on the rear only. Take to 45/55. Now if no vibes put the front shaft back in do the spin test if no vibes put the front tires back on, do the speed thing again.. Now everything should be back on the Jeep.

Time to hunt down whats really giving the vibes.. Tires and wheels/drums/Drive shafts so on. Strip all the possible stuff that causes vibes when driving. When on Jack stands and you do a spin up test you will see how smooth stuff is.. Vibes will pop up right away and show you the problem when you add one peace at a time. You will notice how smooth the Jeep feels when just one drive shaft is connected . I know its a lot of work and messing around,, but hell that's the fun part..

 

If you run it with no drums please do not step on the brakes at any point.

Max

 

^^^^^ that is a good point. It can be habit to hit the brakes lol.

I just let the jeep spin down on its own by putting the jeep into neutral after spin test..

 

luckily I don't have drums to worry about, got rid of those a while back.

 

I'll give this a try this weekend hopefully. The hardest thing is all of my tools are an hour from me. That makes everything that much more difficult and I usually only have time for one or two things when I'm back there because I have so much other stuff to do also. I wish I had like a 4 day weekend or a shop down here I could borrow or something.

 

I hear ya,, you will find it don't give up.

Who installed your gears again? I forgot.

 

a guy lowrange recommended

 

Lowrange here? If so I would trust who he said to go too.. I'm sure the gear install is fine.. Do that test when you have time.