Whirring sound only heard from inside

[Z.m4v]

At a bit of a dead end here. 96 jeep xj 2wd with the 4.0
About a year ago when driving I noticed a whirring, dragging like sound that got better with each shift. The jeep would no longer go into park, it would just roll when in park. Assuming the transmission to be bad I found another 2wd from a 2000 xj. Did all the necessary things to make if compatible and I have the same noise. The noise is only heard on the inside I'm drive/reverse. However, I disconnected the drive shaft and ran through all the gears again, no noise this time. The jeep is on jack stands right now and I'm not sure where to go from here. It has a chrystler 8.25 rear end. Is it possible that I got 2 bad transmissions or is it something more rear end related. I drove the jeep in lefthand circles and there was some skipping of the tires. Any help is appreciated

 

[Unclewolverine]

It doesn't take much washboard in a u joint to make a racket, that's where you should always start with a driveline vibration or noise. Front wheel bearings can make noise/ vibration too.

 

[Z.m4v]

It doesn't take much washboard in a u joint to make a racket, that's where you should always start with a driveline vibration or noise. Front wheel bearings can make noise/ vibration too.

If the noise goes away with the driveshaft removed, does that necessarily disqualify the transmission from being the culprit

 

[RCP Phx]

No, but I would also be suspect of a pinion bearing!

 

[RCP Phx]

Also check the slip yoke!

 

[Z.m4v]

Also check the slip yoke!

Also would like to mention I an an avid one-wheel-peel enjoyer if that helps to narrow it down

 

[edconceited]

At a bit of a dead end here. 96 jeep xj 2wd with the 4.0cluster rush
About a year ago when driving I noticed a whirring, dragging like sound that got better with each shift. The jeep would no longer go into park, it would just roll when in park. Assuming the transmission to be bad I found another 2wd from a 2000 xj. Did all the necessary things to make if compatible and I have the same noise. The noise is only heard on the inside I'm drive/reverse. However, I disconnected the drive shaft and ran through all the gears again, no noise this time. The jeep is on jack stands right now and I'm not sure where to go from here. It has a chrystler 8.25 rear end. Is it possible that I got 2 bad transmissions or is it something more rear end related. I drove the jeep in lefthand circles and there was some skipping of the tires. Any help is appreciated

I just tried disconnecting the drive shaft and running the gears again like you said, and indeed the noise is gone. But I'm not sure if this will last long. It's still better to find the main cause of the noise. I suspect the sound is from the gear bearing.

 

[Z.m4v]

I just tried disconnecting the drive shaft and running the gears again like you said, and indeed the noise is gone. But I'm not sure if this will last long. It's still better to find the main cause of the noise. I suspect the sound is from the gear bearing.

The pinion bearing like RCP phx said?