"Wayne.B" wrote in message
...
On Wed, 05 Aug 2009 12:44:28 -0400, Little John
wrote:

Our truck, a Navigator, has a button on the end of the shifter lever.
It locks out the top gear, so the box doeesn't hunt for gears.

Casady

I could just drive in 4th, which would lock out overdrive, but don't
do it unless I'm towing in a pretty hilly situration.


It's better for the transmission to lock out overdrive anytime you are
towing.


Since my towing capacity is about 16,000 pounds, I will only put the tranny
in tow haul mode when in the mountains. Even not towing, I use the tow haul
mode for engine braking in the mountains. Was nice coming over Sonora Pass
a week ago, to not use the brakes much coming down off a 9600' pass.