Rear driveline vibrating and grinding and making all sorts of great sounds.

[iant333]

Yeah this has been the case since I installed my new rear springs and gears a few weeks ago. I figured since when i did the springs I took the shims out that the pinion angle was off. Well I made the pinion angle perfect today and it is even worse, like noticeably worse so apparently the pinion pointing directly at the transfer case was better than it actually being correct.

It grinds when it is coasting, like pretty loudly, it makes almost the exact same sound as when the slip joint on my front shaft was bad. Once you get on the gas the grinding stops but it vibrates really harshly at any speed over 45 and it seems to come in waves and get better and worse over a cycle of like 5 seconds, the vibration is actually so bad I cant see out the mirrors at speed since they are shaking so much. There is also a ton of slop when im driving it, if you are coasting it takes half a second to catch once you get back on the gas.

Im almost 100% sure it has nothing to do with the gears, the pattern and everything was perfect when i installed them and they still look fine now, I have an Aussie in the back which might explain some of the driveline slop but it was all in spec when I installed it. Obviously it isnt anything to do with the pinion angle, all the u-joints are fine and nothing really looks out of the ordinary.

Im at a total loss for what to even look at next besides just throwing the whole thing in the trash and getting a SYE and new shaft and hoping that somehow it might fix it. Any ideas? I'm thinking maybe it is something in the transfer case is screwed up and it just happened to appear around the time I did all this stuff to it.

[Ruepart Hoaxley]

If there was a pre-existing problem with the t-case, changing things in the driveline would definitely make them more prominent. Does it shift in and out of 4wd fine?

When you did the gears, did you torque the yoke on correctly?

[iant333]

The yoke is fine. And it shifts fine, I was thinking something along the lines of a stretched chain.

[LittleD]

How'd did you set the pinion angle? did you try having some one get on the gas/brake while you check how much movement the rear end has?

Edit: did you make sure everything is tight?

[iant333]

How'd did you set the pinion angle? did you try having some one get on the gas/brake while you check how much movement the rear end has?

Edit: did you make sure everything is tight?

I eyeballed it, but it was close enough according to my friend at the spring shop, he said pinion angle isnt going to cause grinding like what I have anyways, especially not if it's close.

I looked at the bottom with everything going and it doesn't look like anything is wobbling but it sounds like it is coming from the driveshaft/t-case area.

Everything is very tight.

[Zullock Holmes]

That sounds like what my jeep was doing, for me it was a tcase issue. i blew up 4low and that stretched the chain so everytime i coasted it was grinding on the inside of the case, but also the front output yoke had some play and thats where my vibrations were coming from. check out your tcase.

[1cleantj]

start by pulling your front driveshaft, rule that out, it may have to much play in centering ball or splined section.

[iant333]

I pulled the rear shaft, and the vibration stopped while I was FWD'ing it.

I think i'm gonna just get an SYE and a front shaft and hope it fixes it rather than fucking around with the stock setup.

[LittleD]

Whats the condition of the rear shaft? sloppy?