Howdy-

 

So I have an 86 gl, ea82. I went out fishing today in the mountains and when I threw it in 4wd I noticed this loud like clinking metal on metal noise or something. It sounded like it was coming from the rear end. When I took it out of 4wd it went away. As I increase in speed the noise also increases. I was out just a few weeks with it in 4wd and I didn't hear anything like this. What could be causing this? and what might have caused the change. Thanks

Could be a u-joint in the driveshaft or possibly a rear axle or differential problem. From your description the noise is caused only when the rear output is put under power and doesn't occur when all those components are just coasting. I would get it up in the air (all 4 wheels) and starting looking for damage and shaking things to see if the driveshaft or axles are loose in any way.

 

GD