Share 'Advice On Travel Trailer Towing'

I have a 2008 Tundra 4x4 DC SR5 TRD towing a 8500lb Jayco 32RLS Travel Trailer. There are a few issues I can't seem to find the answers for from my dealer regarding trailer towing: 1. When towing the trailer in tow mode - All other pickups I've owned the truck will not shift into overdrive when driving in the tow mode. With the Tundra it seems it will shift into 6th (high) gear regardless of wh...