99 cherokee classic, 6.5 rc long arm with 33 bfg km2's and new wheels also, sye and tatton shaft also new.

I have a pretty good vibration/drone noise at about 35-50mph
once i get the vibration, you can shift to neutral or left off the gas and it seems to go away, so I really don't think its in the tcase or rear end, since they are still spinning at the same mph whether your coasting or in neutral.

sent pics of the rear driveline set up to the company I bought the lift from and to RC and both agreed the driveline looks to be in good positioning.

Any other ideas?

Tires are brand new and were rebalanced again just to be sure its not them.
also definitely feels to be coming from behind the front seats so its got to be from the tranny/tcase going back

 

Have actually checked your driveline angles with a gauge? Or are you just eyeballing things. Also check bearing and Trans/motor mounts.

 

I did not check with my angle gauge, I took pics like I was instructed by the guy at RC and the company that sold me the lift kit, both said it looks great and see no reason for vibration, so i took it as gospel, but I'm sure you can't eyeball a 2 degree variation off a camera, I'll check tonite.

Bearings show no slop in the rear end at the pinion, but trans or motor mounts very well could be, is there a good way to test them?
I got underneath and tried moving the trans around at the tail shaft with no success so I'd assume its ok, but you never know.

 

You gotta actually look at the mounts and see if there are cracks, rotting, or full on deterioration. As for your driveline, the u-joints are under load when you're on the throttle. When you let off or put it in neutral they're no longer under load, so yes, it does make a difference.

 

after crawling under there, I got at least 1 inch up and down of play when I push on it so I think there lies my issue. I don't remember it being like that, but maybe I forgot to check it before, or thought I did.

Anyways, is there a better mount than others or just grab one from oriellys??

Also can I remove it (mount) without having to remove the trans cross member, or do I have to remove that damn thing, lol.

 

Brown Dogs is by far your best option. Might as well do motor mounts as well, and yes, you gotta drop the crossmember.

 

Brown dogs are great but he's a one man shop so it does take awhile. Mine w/brackets took about 3 weeks. Well worth it if you have the time! There are several other aftermarket-better-than-stock options out there. (IronMan, M.O.R.E., ruff stuff etc.)

 

on iron man and ruff stuff I don't see anything for the xj, zj only on iron man, do they make them you just have to call?

 

http://www.ironman4x4fab.com/Products/images/STD-MM.jpg

As for ruff stuff, he said he was going to build some a few years ago. I don't see them on his site but I'd give him a call (this was in like 2010)

Currie also sells some
http://www.currieenterprises.com/ces...t.aspx?id=1180

 

oh, I'm talking tranny mounts, and your talking motor mounts, that's why I'm not finding them, lol. I'll just get a parts house one to start and see if that fixes it and then I'll order from BD or ironman for the motor mounts, for my engine swap.
thanks though

 

BD also makes the trans mount. Just an FYI.

 

a few things to consider...
did you get an alignment after the lift?
also, your drive shaft u-joints are now running at a different angle, so if the are the same ones as before the lift, they are not running in the grooves so to speak as the were before.

and, with the sye, how is the drive shaft angle, it should be different than no sye. your axle pinion should be pointing towards the t-case output now.

congrats on the long arm, you will appreciate the ride and flex now.

 

no alignment yet, drives straight as an arrow, no wandering no vibes up front.
all new u joints and shafts also.
sye angle is good, I'm sure its the transfer case mount, its got some good play in it, hopefully I'll tackle it this weekend.

 

got the tranny mount installed, vibe seems gone, but drone noise is still there.

Can someone post the link on how to properly measure driveline angles?

 

The drone could just be the fact that you're running big ol' knobby mud terrains too. Just an idea.