Well thanks for the input will start to look in transfer case I guess . Does any one think it could be in front axle?

 

if you had a problem with the front axle you would be experiencing a constant grinding noise, not just when you are engaging 4wd.

Also just to check, you are shifting into 4wd while the truck is in neutral correct?

If not that might be why you are getting a grinding noise... you might not be following the correct procedure to switch into 4wd from 2wd...

 

Yep I'm shifting correct. It isn't like that its after i shift and start to move is when the grinding noise starts. think got a bad axle or chuck. doesnt make the sound when in 2wd only in 4wd with a load on it

 

Any metal shavings in the trans/transfer case?

 

Didnt find any when i put new fluid in it just thought I would try that but did not help.

 

it is definitely possible that you have a front axle that is damaged, or possibly you might have something going on inside of the transfer case... might be time to get it cracked open and checked professionally.

 

Well turn out it was the chain and drive gears in transfer case. Thanks for the help.

 

glad you found the problem, hope it didn't cost you your first born son to repair...