4L60E Issue 00 Silverado z71

I was stopped at stop sign. When I gave truck some gas to go I heard a loud clunk and now I truck will no move in any gear. No issues prior to this. No slipping no burnt fluid smell. Tansmission only has 46,000 mile on it. It's a Jasper reman and unfortunately the warranty is out. Any ideas what may have happened.? Truck has a 4.8 motor and was running flawlessly until now.