97 Chevy Suburban 1500 4wd just started grinding noise under hard acceleration or under load from underneath. Maybe transfer case or transmission area?

If I let up on the gas it stops immediately. Once I'm driving it sounds perfectly normal. Transmission operates normal. Shifting transfer case to and from 4wd is normal.


This one really has me baffled as driving down the road it seems normal. I only get the noise with a hard acceleration. Sounds like gears slipping or grinding.

Checked all the u-joints which I greased a couple days ago and they're all tight. Output shaft seems tight at the driveshaft. No leaks except the transfer case is dripping some oil slowly, but hard to tell from where as it's coming from above.

Swerving on the road seems to eliminate any wheel bearings as I can't reproduce it that way.

It almost sounds like gears grinding momentarily and when I let up it goes away. And I checked with the AC off, so it's not that.

This all just started at the end of a 800 mile drive today.

I'm in upstate NY for my sons college graduation and I hope we don't get stuck far from home!

Any help or ideas would be greatly appreciated!!!

 

Welcome to the forum.

Rear wheel bearings or rear diff?

 

It seems like it's coming from farther up front. Under the front seat area. And only under hard acceleration in 1st or reverse or starting on a hill.

 

Turned out that the chain was jumping in the transfer case. We ended up installing a used one and made it home. But my 4wd is not engaging up front, but it seems to be the solinoid on the front differential I believe.

The transfer case is engaging the driveshaft, but not turn the wheels. I have voltage to the solinoid, but it's not moving.

 

I'm having the same problem any answers plz help???

 

Too much clearance in the rear diff pinion causes this when on the gas. I have the same issue right now for over a year it has sounded like a school bus