Bearing Noise? transmission or t-case???

Just installed new Brown Dog rubber motor mounts and a new transmission mount. Old mounts were completely shot and apparently disguised all sorts of issues.

The issue that worries me the most is a whirring/faint grinding noise, think it's a bearing but not completely sure. I never heard it untill the new mounts were installed. The transmission mount was so shot the new one raised the transmission/t-case at least 2", if not more. One side was completely separated and the other side might as well of been.

I have an AW4 and NP242

Noise is present when:
-Driving at all speeds, speed of noise increases linearly with speed, under power and while coasting, slightly louder as load increases
-Transfercase engaged in 2wd, 4wd part & full time, and low range, noise seems to increase in speed when driving in low range vs high but I'm not sure if it's because rpms are increased or t-case is spinning faster, the bearing noise increase doesn't seem to match the speed of the usual low range gear whine
-Transfercase in neutral


No noise present when:
-Parked
-In gear but not moving
-Transmission in neutral with varying engine rpm


It was dark so I stopped working on it but plan to crawl under tomorrow and try to pin point the noise. But was hoping someone would have an idea what it might be

did you possibly buy the wrong transmission mount? i know daystar sells a couple different ones ranging from 1 1/2" high, and a 3" high mount. if it raised your transmission/transfer case a good 2 inches, you may have needed the shorter one.

hmm don't know, I'll look into it. I didn't buy the daystar mount, just an O'reilly's special.

My old mount was completely collapsed on its self so I wasn't surprised it raised th transmission/t-case some

I don't see how that would cause the noise I was hearing though?

What year is your jeep?

1989

*Damn to late to edit the original post

I have a 1990 with the NP242 (3 1/2in lift) and just replaced the exact same mounts as you. except with oem rubber.
I immediately had an issue with my exhaust rattling against the crossmember AND the shifter for the T-case making a crazy rattling/grindy noise (just used some grease on the linkage)

i still had a funny noise... but i figured it would go away, my Ujoints on the rear DS were completely gone in about 2 weeks, after replacing those the noise is almost gone but im pretty sure its the front pinion bearing.
Check your driveline after you figure out your grinding issue

So I'm confused. The noise is gone. Last night it was present the entire drive home, aprox 45 minutes and now today i've been driving all over town and the only noise I heard was a similar sounding noise that only happened twice real briefly (like less than 5 seconds each) when I got on the highway for a few miles.

Maybe the mounts settled in. What style transmission mount are you using?

Don't remember the brand but it's just a stock style rubber mount from O'Reilly's

Well the problem persists. I've discovered that it only makes noise when at opperating temerature. I can drive around town all day and not hear any noise, I live in a small town. However, once I drive it at speed for a few minutes the noise returns and continues until t-case has cooled.

I put the rear on jack stands and ran it in gear, I'm pretty sure that it's coming from the t-case, somewhere on the main shaft near the center.

I'm now shopping for a rebuild kit and I'm leaning towards the novak kit... Anyone have any experience with this kit? I like that it comes with a chain.

I'm trying to decide if I should put in a new oil pump or not. In all the t-case rebuild threads I've reviewed it doesn't seem like a common practice. Opinions?