Another vibration thread.. Diagnostic input appreciated

Vibrations felt and heard throughout jeep after 55mph.

Hack and tap SYE, both drive shafts rebuilt, sized, and balanced.

New 4:56 gears with Grizzly Yukon locks. D30 and 8.25.

New 32" muds

Rear pinion 1 degree lower than the drive shaft. Same vibes as 3 degrees lower.

Front ds removed, same vibes.

1. Should I be able to shake the transfer case a little bit? Could the T Case mount be bad and causing vibes?
2. Should I try and remove the rear pinion 4 degree shims and see what happens?
3. Can the rear leaf springs be installed wrong? (left on right, etc?) Bottom leaf in the pack seems to turning/rotating. New RE 4.5 leafs.
4. Can I pay someone to fix this shit?

Thanks!

Take out the rear shaft. see if it goes away. If it does its related to the driveline. It kinda sounds like it isnt tho, as you stated the same vibes were there after changing the angle. Could also be the tcase shaft not being cut square

Yep, pulled the rear shaft and got to 65 and its much smoother.
I'm going to pull the rear shims and try again this weekend.
hopefully I don't need to resort to a
full

Maybe your leaf packs are tourqing up a bunch and you need more then 1 degree?

mako my day said:

1. Should I be able to shake the transfer case a little bit? Could the T Case mount be bad and causing vibes?
2. Should I try and remove the rear pinion 4 degree shims and see what happens?
3. Can the rear leaf springs be installed wrong? (left on right, etc?) Bottom leaf in the pack seems to turning/rotating. New RE 4.5 leafs.
4. Can I pay someone to fix this shit?

Thanks!

Click to expand...

1. No, your tcase should be rock solid. I would swap the mount. They cost something like $15 shipped from RockAuto.com
2. If you measured the angles correctly, don't pull the shims.
3. No, left/right doesn't matter. If you put the spring in backwards, you would know because the tire would be WAY offset from the wheel opening.
4. Yes, but why do that? You can fix this.

Thanks weirdo. I'll report back Friday after i change the tcase mount and checking it all over again.

My jeep vibes too, my issue is the tcase front bearings, but I have been swapping parts and such...

The tranny mount for me made a good difference
Motor mounts made a small improvement, worth doing either way
The angles are crucial out back, check and double check for the perfect setup


DO NOT rule out a loose pinion somewhere, my front D30 yoke was rebuilt properly, but the yoke worked itself loose, ruining the front u joint, and I think it helped ruin the front tcase bearings.

Vibes are more than just an annoyance, they destroy parts.

put a tack weld on the hack and tap yoke to keep it from moving. that spline/slip fit isn't perfect all the time.

first make sure motor mounts, tranny mount, are solid .

then make sure the pinion u joint is not worn on both front and rear. then isolate the issue by removing one DS at a time and get up to speed. see what happens. consider taking the shafts to a shop to get balanced.

get tires balanced. get balance sheet. for the most part that should cover.
once you get tires and DSs balanced youll know pretty quick.

front DS, rear