OD or Transfer case issues - qudra-trac NP249
I have a 1995 Grand Cherokee with 4.0 6cyl and NP249 Quadra-Trac. When the transmission shifts into 3rd gear in OD mode there is a high-pitched whine and a scraping noise. This gets loud on acceleration but even louder when I let up on the gas and it's coasting. I've been told by one mechanic that it was the Transfer case but yet when I turn off the OD it drives quietly and shifts just fine through the 3 gears. So it's confusing as to what it may be. I had a new transmission and OD put in about 14 months ago so I'm believing the Transfer Case also. I bought a used Transfer Case and delivered it to a 4x4 service garage in town. The shop can't look at it until next week. I'm wanting some input as to whether it could be the Transfer case indeed or the OD. I'm able to drive the car with the OD turned off but wondering if that's because gears in the Transfer case for the upper speeds may be stripped or the chain stretched and is jut more taunt when the OD is turned off or whether it's a problem with the 14month old overdrive.