June 26th, 2011.
I'm not challenging the OP here, but as for Digitaldust, if he's hitting 70+ in a stock M109 shop truck, several things are out of whack... 1. The Speedometer; 2. The GPS; 3. He's dropped it off a tall cliff.... There is no way a stock multifuel will hit those kinds of speeds with normal gearing and still have an engine left in the truck. My M35A2 with cargo cover will go 11-12 mpg if not pushed above 45-50, and with the 11:00X20 NDCC's on her she will red line at 60 MPH and the is just shy of blowing the engine out of her. What I will say to the OP is that if you are doing above 45-50 consistently, you probably are shortening the time to rebuild or replacement for your engine, as the long stroke diesels used in the deuce were not speed engines but rather torque engines...
If the duece is run below or above 80% normal output for very long, maintenence issues will be the result. These were designed as off road trucks, hence the tactical designation, and they are really intended for slow speed work in conditions a stock highway truck could not survive in. That is why there is no interaxle differential on the rear end and why the Army used a walking beam suspension system, not sophisticated, but reliable under the circustances. My truck's hour and speedometer togather indicated an average uise speed of about 22 MPH for the whole of the time she was used by the Army and her two prior civillian owners, and I have only upped it slightly as 98% of her time with me was spent in the mid 20 mph range... Even though she was used on several road trips of great length (for a stock deuce), it still worked out to the original speed range being the normal for her.
Next time you are doing 90 in gear, get a state trooper to radar gun you.... I'd like to see the report visually confirming that speed with the truck in gear.
![fat lady sings fat lady sings fat lady sings](https://www.steelsoldiers.com/images/smilies/opera.gif)
Plus, fuel economy in a deuce, NOW there's an oxymoron!