Grinding in either transfer case or transmission

[ttpankt4]

Hi I have a 1990 nissan d21. Its the 4cyl 4x4. When I put it into 1st 2nd 3rd and 5th gear, I get a very bad grinding sound. Like the sound of turning rotors. When I put the truck into 4th gear then the noise goes away. It only makes the noise when I let off the clutch and push the gas pedal down. Does anyone know what this could possibly be? Thank you

 

[Bigredmariner]

Sounds like the bearings are shot, probably won't be long until you hear the same noise when in 4th gear.

 

[Black02Silverado]

I agree with Jarrod, sounds like the bearings. How many miles are on it? Is the fluid at the correct level?

 

[Zembonez]

Manual transmissions were notorious for eating bearings. Very rebuildable and a pretty easy fix if you yank it before it craters completely. I doubt it's the transfer case.

 

[ttpankt4]

It has 272xxx miles on it. It has sat for 3 years. I'm not sure how much driving its had but I just bought it Saturday for 700 buck and drove home about 100 miles with a lot of stop and go traffic.