When I cut this on what does it do to my truck/transmission.
I have a 2002 I pull a mower XMark and some blower, weedeater. equiptment.

Do I turn this on or just run in 3rd? Which is the best for the truck..
One guy said put light on and run in 3rd. One said just run in 3rd.
What is best for my truck with 115,000 4x4

 

just run it in 3rd unless there is a lot of hill's on the highway flat and level no wind run in overdrive ,watch trans temp gauge .

 

With my truck, 2000 Z71, if I'm pulling a heavy load I put it in trailer towing mode.
If I'm going up and down hills, and the truck keeps shifting out of overdrive, then I drop it to 3.
This just keeps it from shifting up to overdrive, otherwise it shifts like it should.
If it keeps shifting in and out of overdrive, the fluid will get very hot and you will smell it.
Not good on the transmission at all.