One problem after another. TH400 shift issues

[cadillac_al]

That's what happens when you plow in high range. GM gave us low range for working. I still doubt that would kill a 400 though. I'll bet there was something up with the vacuum modulator. The valve itself must be stuck or something in the valve body. It should last a long time with a full rebuild.

[GRADYS Performance]

If you are plowing with the truck put the Largest auxiliary cooler you can fit on your vehicle to assist the cooler in the radiator with cooling your transmission fluid. To high of fluid temp is one of the fastest ways to damage a transmission.

[Orion88]

I won't be plowing with it anytime soon. And I wasn't the one who was plowing with it when it got overheated. Like I said, I plan on replacing the front and rear diffs with lower gears down the road. That will be an improvement across the board (except fuel mileage).

[GRADYS Performance]

If you plow, You NEED the largest cooler you can fit. The gear change will have minimal change to the trans fluid temp when plowing. No air flow through the radiator due to low vehicle speed and lowest efficiency in the torque converter due to high load and slow speed cause tremendous heat build up in the fluid when plowing snow. Granted spring is coming but doing it before you plow next winter is recommended.

[Orion88]

What I meant is I think this truck is being retired from the fleet. It was always a backup truck anyways and only saw plow time 2-3 times. My dad's fleet is more modern vehicles nowadays. He bought this truck cuz it was a good deal, a cool truck, and made for a cheap plow truck. Even once I replace the front and rear ends I still don't think I want to plow with it. I'd like to keep it from rotting away if possible. It's in fantastic shape but its starting to show its age