Grinding noise

[Betsy]

1990 6 cyl 5 speed makes horrible grinding noise in 4wd. Doesn’t make the sound in 2wd. Sounds like it’s coming from the rear right side. Transmission, transfer case, bearing, axle?  Transfer case was rebuilt 2 years ago. 

[Dzimm]

Since it's only when in 4wd I'd start looking at the transfer case since all drivetrain components spin in 2wd except the tcase.  The transfer case is the only thing that changes when 4wd is engaged.  

 

The only thing I could think of other than the t-case is if the gear ratio was different front to back but I think you'd have more severe problems than a squeak if that was the problem plus I think you'd know that already.

[yxmj]

Does it make the noise in 4H and 4L ?

The video from my end sounds like a creaking.....?

[Wallace Krempa]

On 10/11/2019 at 4:25 PM, Betsy said:

1990 6 cyl 5 speed makes horrible grinding noise in 4wd. Doesn’t make the sound in 2wd.

 I have a 89' with a 91' 6 cyl. I have to put mine in 4wd every morning on my way out because my driveway is pretty steep on stone. I noticed the same thing. I replaced the oil in my front axle and tranny. Seemed to fix it, even with long term driving in 4wd.