So a started hearing a loud wirling noise anytime the truck went more than 25 mph. noise would quit immediately if i shifted to N. Did some more fiddling and it will only happen if I leave the OD on. if i shift it off the noise stops. Any ideas on this one?

 

Disabling over drive shouldn't make that much of a difference.... can you tell where the noise is coming from? Is it indeed the trans? Could it be the t-case?

 

Possible. Physically the case looks fine. I changed out the fluid with no effect.

 

Wonder if the chain is getting stretched..... Although, that shouldn't matter in 2wd.

Will it make the noise if you raise the rear off the ground, and run it while stationary? (makes it easier to localize the noise.)

 

determined its coming from the rear side of the transfer case. also happens regardless of OD status now

 

Pull the tailshaft housing off the t-case, check and make sure the snap-ring that holds things in place hasn't abandoned the shaft.. (common failure)

 

Snap ring is in place still. No visible damage to case exterior or rear shaft

 

how do the bearings feel?

 

Pretty smooth

 

hhhmmm.... Didn't put new exhaust on it by any chance, did ya? (so you can hear all the neat noises it makes.... )

If everything seems ok, think I would just run it, and see what happens.