M1165A1 high RPM at 55mph

[Mogman]

I think most were 2.56:1 , the Alpha was 2.56 and the early years had TH400 transmissions so no need for higher (numerically) gear ratios

 

[Coug]

Random answer, usually 2.73 or 2.56, or whatever the owner decided to put in there.

EDIT: Changed 3.08 to2.56 because unlike military HMMWVs, they went to a taller gear in later years for lower cruising RPMs as opposed to lower gearing for higher torque in the military ECV/REV trucks.

92-97 had 2.73 gearing
98+ had 2.56

1998 Hummer H1 Model Year Changes and Buying Guide.

www.lynchhummer.com

So I went back and corrected myself, as it appears they went to higher speed gears rather than higher torque in later years.

Here's a sales ad from 1993 stating 2.73 gearing

 

[darkslide750]

If you have the smaller pulley you should change it, there is no need to use more of what little HP you have over spinning the alternator.
Your truck was basically turned into a mobile power supply/transportation for battle ground electronics, its main purpose was to sit for days at high idle in one spot.

Does anyone have the part number for the larger pulley?