If you are stuck with the Hummer as a tow vehicle, Never tow in Overdrive, keep your eye on the guages and change your tranny fluid if it ever gets hot. In my 580hp Dodge Diesel PU truck I change fluid ever 6000-10000 miles.
This site has some good info.
Good Luck
http://www.goerie.com/fallcarcare/ch..._fluid_is.html
<font color=Gray>Pewter</font>, Lux, No Spare Anywhere
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Foose Wheels,
Corsa Touring Exhaust,
HID's