I just had my tranny flushed and filled at the dealership at 33,000 miles an now have 35000 on the truck. On Monday coming home from Reno over Highway 88 the tranny was not acting as it has in the past. There were times (with Tow/Haul on) when I would tap the brakes and it didn't shift down like it should. Then one time kind of out of the blue, with foot off the throttle the tranny shifted down REAL HARD I mean like someone rear ended me. It didn't do that again but it was a he11 of a hit. No codes have shown up so I don't know if I should go back to the dealer or not.

I should add that we went up over Donner Pass on the way up and as I said, over 88 on the way back in about 95* heat and the hottest the tranny got was 185* and was mostly around 171 to 175*

The ETC topped out at about 228 on a long pull and the EOT at 232, both came down rather quickly when topping the hills. All of this while pulling a 10,800# 5th wheel.

Other than the tires/wheels (from an KR F350) and the air bags this truck is bone stock. Other than the shifting coming down hill the truck performed great the whole trip.

Thanks
Steve

 

The occasional hard downshift is, unfortunately, a trademark of the TorqShift. It's a very complicated transmission and sometimes the adaptive software doesn't quite track what it should.

If it does it again the first thing I would try is clearing the adaptive memory. You can either disconnect both batteries' ground straps, or WITH THE KEY REMOVED FROM THE VEHICLE unplug all three connectors on the PCM. The PCM is between the driver's front fender and battery. Leave everything disconnected for at least 10 minutes.