Chevrolet Repair: 1999 chevy 1500 4wd, chevy 1500, first timers

Question
I was backing my truck up then put in drive I heard a clink and the truck jerked and now no reverse.


Answer
Sounds like the reaction shell in the trans broke.....common problem with the 4l60e trans.  There are updated parts from GM to replace this, but requires you to completely disassemble the trans.  If you are not familiar with doing trannys, I strongly recommend that you take it to a shop.  It is very difficult for first timers, and even harder if you don't have the special tools to do this task
JImmy