1995 Dodge Caravan won't Move

Van starts and runs good always has. Engine was replaced around 40,000 miles by a dealer.(Bad rod bearing)1n 2000 transmission was worked on by aamco and was sent back two times for rework due to leaks. Five years ago had transmission resealed due to a leak. No problems up untill now. While driving down the interstate started to shake and make noise pulled off the roadway to a truck stop. At this point the van stoped moving. Towed home looked at it. It starts and runs but will not move when put in gear. Sounds like the transmission goes in gear but makes noise like a gear or something has sheared off or the diff went out. Any idea what it could be? Van is not worth spending $1200 to have it repaired.