Diagnosing Drivetrain Whirring

Hello all,
New to the forum, but not to vehicles. Just bought myself a project MS6. Previous owners swapped in a JDM engine to replace the blown one a couple years ago. Now they were selling it due to drivetrain noise. I took it for a short test drive and the transmission shifted fine, but there is definitely some gear/bearing noise. I have not had the opportunity to get it on jack stands yet and check fluid levels, condition, etc.

My question - is there some definitive way to tell whether it's the transfer case/PTO or the transmission without major disassembly? With all the videos and posts I've seen about transfer cases I'm guessing that's the problem, but I wanted you guys' input.

 

Lucky that JDM motor is not blown yet. Those are garbage. If there is aftermarket mounts it could be why. But really need to get it up in the air and physically inspect.

 

Do you have any video of it with good sound? If the trans is shifting OK, I doubt that's the source. A couple things to help diag:

1) Front or rear - It might be easier to hear diff whine if you fold the back seats down. That made it super obvious when my rear diff died. Link to video

2) Drain the fluids. Heavy glitter is normal for both the transfer case and diff, but chunks of metal are a telltale sign of failure. I think you can pop the cover off of the rear diff while it's still in the car, so that might be an easy way to inspect it more thoroughly if you need to.

 

I can get a good video tomorrow - I can try folding the seats down to see if it changes but it seems to be coming from the front. What's the best way to upload on here?

 

See if these work. It is louder in person than the video is showing.

https://photos.app.goo.gl/7jinzQVgUKJJxzk97

https://photos.app.goo.gl/gyNn7vmAs7y3JWEHA

 

LOL that's awful.

I think I would drain the PTO first, that's the most likely place.

If you get it up on 4 stands, you could probably drive it in the air and see if that helps you locate it, and let's you know if you have rear drive or not.