Oshkosh M911 was one of the U.S. Army’s main heavy tank transporters during the 1980s. Paired with the M747 semitrailer, it was designed around loads of roughly 60 tons. That figure looked generous until the Abrams kept gaining weight.
A Detroit Diesel 8V92TA two-stroke V8 delivered 430 hp, backed by an Allison automatic transmission and a two-range auxiliary gearbox. M911 used an 8×6 drivetrain, a liftable pusher axle and two hydraulic winches mounted behind the cab.
Everything about the truck was built around controlling weight. One number still mattered more than the rest: 60 tons.
M1A1 Abrams tanks eventually moved beyond that range. Army documents from the early 1990s describe the M911 and M747 combination as overloaded when carrying the M1A1.
Durability suffered, and road speed could fall to around 15 mph in some operating conditions. Experience during Desert Shield and Desert Storm showed that the problem was no longer just a specification on paper.
M911 could still haul the tank, but the transport system was working with less and less reserve.
Oshkosh answered with the M1070 and M1000 Heavy Equipment Transporter system, designed for the heavier Abrams.
M911 had not failed at its original job. Its cargo had simply outgrown it.
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A military based Mack Super Liner 6×6 begins a demanding 999 mile drive across mountains and desert highways.
My brother drove one in the Army. He would pick up tanks at the airfield and haul them to the base. Sometimes he would take shortcuts across back roads and the bridges weren’t rated for 60 tons. The bridge would collapse into the rivers and creeks after he made it across. Also, he went through narrow bridges with the smaller 18 wheelers trying to get across at the same time and would have their side mirrors hanging from his after they slapped trying to get through.
Love that sound, nothing like a detroit diesel!