I had a 2002 Dodge 1500 (no hemi). The rear end went bad within the first couple years and they put a new one in under warrant. After that, no issues. I didn't tow anything over 4,000 lbs, but I'm sure I was close on numerous occasions. I don't recall what the problem with the old rear end was when it was replaced. Good luck, sorry your stuck...
Steve & Sue
2017 Grand Design 297RSTS Travel Trailer
2017 Ford F-350 Lariat Crew Cab diesel 6.7 SW LB 11,500 lb GVWR package
Former: Crossroads ST26RB