[VAC] Re: Towing in Overdrive

[KEVIN D ALLEN <overlander64@xxxxxxxxx>]

Greetings Dave!

The dealer and my owner's manual both supported towing in overdrive with my
'99 GMC K2500 Suburban with the 7400 VORTEC.  As directed in the owner's
manual and by the dealer, I always downshift manually as soon as the
transmission begins to hunt.  The Suburban now has over 70,000 miles and
more than 40% of that was towing my '64 Overlander.  The transmission was
just serviced for the second time (35,000 mile intervals as per Dealer
Recommendations), and as with the first time - - the oil was still clean and
unburned.  I am continuing to use the factory installed transmission oil
cooler and engine oil coolers that were part of the 10,000 pound trailer
towing package.  With this rig, my solo MPG averages around 15 MPG and my
towing MPG averages between 10 and 12 (10 in the mountains and foothills 12
elsewhere).

Kevin D. Allen
WBCCI/VAC #6359
1964 Overlander International/1999 GMC K2500 Suburban