NP231, maybe AX15 noise

[ChrisTJ98]

It started as intermittent noise about 3 weeks ago. It would happen when I make a right or left hand turn. I could feel it through my shifter and it would go away with speed. Yesterday it happens when I made a left hand turn, this time I was close to home and kept my speed slow till I got home hoping it wouldn’t fully go away. I should add when it’s loud I feel it through my transmission shifter.



I put transfercase in neutral and shifted through the gears 1-5th gear it was more faint but could hear it. I got my stethoscope out and I could hear it more in the transfer case than the middle of the transmission while transmission was in gear.



When transfercase is in neutral should the input shaft bearing and oil pump be the only thing turning? The noise is almost like something isn’t fully engaged. Transfercase I rebuilt a 1000+ miles ago and replaced all
bearings, seals and chain. Only concern is the Chinese bearings. I kept original bearings and they are NSK usa made except for 2 that are different brand name. I figured if I gotta go back in it I’ll get usa or Japan made bearings.



Anyone ever experience this?

 

[macleanflood]

Turning usually means u-joints.

-Mac

 

[machoheadgames]

I don’t have many suggestions, but if the engine is running and transmission is engaged, then the only thing turning in the transfer case would be the input gear and planetary. The next thing down the line is the range collar for 4Lo/neutral and it being in neutral means the teeth on that collar are not engaged into anything and are not spinning unless by friction.

The oil pump is only pumping if the rear output is turning.

 

[ChrisTJ98]

I don’t have many suggestions, but if the engine is running and transmission is engaged, then the only thing turning in the transfer case would be the input gear and planetary. The next thing down the line is the range collar for 4Lo/neutral and it being in neutral means the teeth on that collar are not engaged into anything and are not spinning unless by friction.

The oil pump is only pumping if the rear output is turning.

It’s very strange, it did it again this morning with a right hand turn. Almost needs to do it constant to figure out where it’s coming from. It’s gotta be transmission or possible input shaft bearing of transfercase. I think when I fix the ac in my other car I may just go back into this transfercase and if I see nothing then I’ll look into rebuilding the ax15. I better start reading up on the details of rebuilding. Thanks

 

[ChrisTJ98]

Turning usually means u-joints.

-Mac

Not if transfercase is in neutral and it’s doing it.