Q: Won't shift out of 4*4 low

Im coming to u I need serious advice I have a 98 GMC sierra k1500 first the transmission that was in it when I got it blew the 3-4 clutch out for starters so I went n got a new tranny put it in wanted to test 4*4 to make sure it worked well it did but didn't bc now its stuck in 4 low so I was told the transfer case motor the transfer case so I changed both of those then it still wouldn't work so was told the transfer case control module so changed it still nothing and it blew the 3-4 clutch in this transmission as well it sounds like its trying to change but all it does is clunk around but won't ever change any advice would be greatly appreciated thanks in advance BTW I've changed all the components and put a whole new transfer case in it and how do u manually shift a transfer case

My car has 211000 miles.
My car has an automatic transmission.