I have a 2004 2500hd 4x4 and when it is warmed up an i drive 10 miles the tranny temp on the stock guage reads 250 then when driving into a plaza to let it cool it jumped to 300 and i could no longer drive past 1st or 2nd gear. says on the screen under the speedo tranny to hot idle an let cool. it takes for ever to let cool an cools quicker when truck is off??? also the seal and sleeve on the rear of the transfer case has slid back to the u joint ??? please help thanks.