I have a silverado with a 6.0 and it pulls my bass like it's not even behind me but it seems to me like I get better mileage when I don't use the tow-haul feature. Will this hurt the transmission in any way??

Pulling a bass boat, you should be fine without it. Just watch your transmittion temp. Basicly all it does is make the transmittion stay in lower gears longer. If your ever in a hilly area and notice the truck struggling, you may want to use it. I have a CC and rairly use it, but my boat is fairly light.

The tow/haul mode is suposed to do a couple of things from what I have read.

-it changes shift points keeping the trans in lower gears longer to help get things moving better and reduce luging.
-it is supposed to increase line presure giving you a better shift with less slit=less heat and wear
-it is supposed to keep the trans from coming out of lockup and overheating, it will stay locked up in whatever gear its in.

I dont think it is necesary to use, but shouldnt hurt it. Personaly I would prefer to get 1-2 mpg worse fule millage pulling my boat 50 miles to the lake than prematurely needing a new transmition.

matt

On my 2010 F-350 the only difference I see is an engine brake when coasting to a stop sign. I use it all the time when towing.

I pull an 8Klb TT with my Tundra and I never use T/H. I put it in select, lock out 6th gear, and roll. 60MPH/2000RPM all day long. If I think it needs to D/S going up a hill, I make it do it. I don't do anything with the boat trailer but hook up and go.

If you have the 6.0, then you hav a 4l80e trans and trans cooler. That truck can haul 8K lbs easy. I wouldent use it personaly. I had a 02 sierra 2500hd with the 6.0 and used the tow/haul button only when pullin a car or stuck truck.