Bobb

Hy guys, I just returned from a 1600 mile round trip with a buddy in his 2005 Dodge 2500 quad cab 5.9 Cummins auto 2 w.d., we were towing one of his antique trucks to a show in California, trailer weight approx. 12000 lbs.. I noticed that on forced downshifts the tach would spike up to 1100 r.p.m. above pre shift r.p.m. and then right back down to pre shift r.p.m.. It was as though during the shift the tranny was not connected to the engine, I told him, if it were my truck I'd take it back to the dealer because I thought something was seriously wrong with it. On our way back to Washington, while pulling a 7% grade his tranny temp went up to 280 degrees. He said the truck has always shifted that way with a load, but I still think something is wrong. Does anyone know what might be wrong? He is going to take it to the dealer tomorrow for a "tranny service" Thanks for any replies, Bobb