Well i just noticed i got a loud clunk sound almost sounds metal from the trans t-case area when i go from park to reverse or neutral to reverse. i noticed it a little bit for a long time but recently this weekend i got stuck cause i couldnt get 4wd to engage which i think is actuator on diff but i had a fair amount of wheel hop which i let off every time it happened. sense this incident i noticed the clunk is allot louder. truck drives fine all gears. u-joints seem tight but might need to recheck to make sure and while under truck and someone engaging reverse sound is definitely coming from t-case trans area. any help or tips would be appreciated limited on work due to apartment complex but i got all tools i need for just about everything. to add i have 160k on original u-joints and i know built trannys can be rough on u-joints especially cause mine shifts hard.and also the 4wd not engaging i checked all vacuum lines and all appear to be connected and in good shape. also no 4wd light but can feel it engaage in low range and high.

 

Remove the front drive shaft AFTER marking the alignment on it and see if it still does it.

 

i replaced the u joints and it still does it i havnt driving it without front drive shaft yet was a little late on reading the post. but when driving at about 10mph today i heard a loud pop from under cab was a metal pop sounded similar to two gears skipping. only did it once and still drives normal. loose or bad t-case chain possibly???