Vibes. not at speeds, but revs?

ok
so I have a 98 2-door with the 4.0, ax15, and np231. im sitting at 3" of lift, no SYE yet.


Im getting Tcase vibrations. there loud but go away if I briefly push down on the 4wd lever. I would just call this an open and shut case of driveline vibration and get a SYE and cv shaft and call it a day. but it doesn't happen at certain speeds, it happens mostly when I wind my gears up real high, like on an on ramp or something similar.

if it was the driveline wouldn't it vibrate at say 60mph because the driveshafts imbalance is resonating at that speed? it happens in high second and high third which are two very different speeds.

I dont know what rpm im at because i dont have a tach.

I have used the search feture and didnt find anything pertaining to this.
I am going to do a SYE either way, just haven't saved up enough money yet

thanks for all the help

most likely the angle of the driveshaftu-joint at the slip yoke end is at its limit. i say its a driveshaft ujoint problem.

Do you have a t-case drop?

Are you saying if you push down on the 4wd lever the vibes go away complete? I'd be willing to bet it's just that, the lever. Check the t-case linkage and make sure everything's good. I'd be willing to bet it's either bad motor/tranny mounts or the t-case drop that's causing that.

I dont have a tcase drop. the handle feels tight when I pull it so I dont think its loose. Ive seen one of the motor mounts recently and it looked ok, at least not rotted or anything. ill look tomorrow to see if I can find the other and look to see if I can find the tranny mounts. I have a feeling your right with the trany mounts.