I just put a snow plow on my truck and the temp gauge goes very high while driving down the road any suggestions on a trans cooler?

 

Could you maybe just put an electric fan on the stock one? You are probably blocking the air from reaching the stock cooler.

 

Your plow is probably restricying the air flow to the radiator. Check to see it radiator is plugged up from the puke bottle, if it is pull it out and clean, that should help. I have a plow on my truck and don't have any overheating problems, but it's usualy pretty cold when i have it on.