48RE 2003 drives like tow-haul

[GSX600]

In hot weather trans drives like it is in tow-haul mode which it does not have. When slowing it engages 2nd gear early. When taking off it hangs up in 1st gear for a while. When this happens the accel. pedal feels like a detent about half throttle. Please help.



2003. 5 2500 QC 4x4 srw, silver, Century cap, lb 48RE 305 hi output 104,000 miles, Discover ATR 265 70 17, Fass 95 fuel pump, brite box, fuel vent kit, Garmin 276C, XM radio.

 

[jray]

My 03 has done the same thing in the past. Time for a fluid and filter change. Probably something sticking in the valve body.

 

[GSX600]

I change the fluid and filter approx. every 25,000 miles with Amsoil ATF. Just changed again. What is strange is that it does this only in the summer.