6 speed auto transmission Allison with 8.3 Cummins

Not being real mechanically steep myself, I would take the Rig to a "good, reliable RV repair shop with a good reputation for quality work and ask them to check out all the issues you are having and how much it would cost to repair all the problems. Then decide if the financial cost is worth fixing or is it time to sell and buy another RV. If you buy another used RV I would take it to the same repair shop to have it checked out BEFORE you buy it. Just my 2 cents worth.