Okay my truck goes into 4hi the light blinks a few times before it does but it does go into it usually. However when i drive around with 4hi on i hear occasional clunking noises.Acctually they happen a lot. When i have been driveing for a few minutes I hear a loud grinding sound. I can put it into neutral and it will stop. when i put it back into drive it will not start again for a few more minutes.

If i stay in 2 hi i have none of the problems.

Also i have replaced both CV joints and i have replaced all the ball joints. When i was replacing the pasanger side CV joint i pulled the "outter driveshaft" or "output shaft"out of thediff a little bit. so i just took out the outer driveshaft. I found the "snap ring" had came off of the shaft. So i put everything back on the way it was supposed to be and put the snapring back on . yes i filled thediff with gear lube.

and it will not go into 4 lo

And a few days ago i got stuck in snow and i had to get pulled out. I checked for ice around the cv joints and stuff anf i cleared it all out, whati could see anyways.

Any sugestions as to what may be wrong ? I think it may be something with the vaccume shifer houseing thing attached to theDiff mabey i didnt get it back on right when i put it on ?