Trailering in OD

[macojoe]

I was alway told by my Tranny guy never never tow in OD!! So I have always left it in 3.
That said when using a GM in the tow mode it changes the shifting to a higher RPM for better power but will go into OD when up to speed. Ford does the same but did not go into OD, thats what I was told on a few year old trucks have no idea in the new? My chevy will go in OD at speed up to my year 2009. either way the best thing if your truck has a temp gauge for the tranny (most newer stuff does) do not tow if the temp is any higher then the engine!