Overview
The M7 Motor Carriage was the production vehicle of the T32 HMC. The T32 was designed to provide a mobile artillery piece and put together the 105mm M2A1 Howitzer on a modified M3 Lee chassis. It was built by several factories and served until the end of the war with the US Army, USMC, Canadians, Free French Forces, and British Army. Postwar use included the Korean War.
There were several identifiable changes during the production run. The early M7 had stowage boxes over the rear deck which opened down and away. On the top of these was a cradle for a small fuel tank which could be jettisoned. The very early ones lacked ammunition ready racks and were equipped instead with four crew seats. Later on, two of these seats on the left side were omitted to make room for ammunition stowage.
As production progresses, some M7 were equipped with the rounded transmission armor cover (E4188) but it does not seem to have been adopted. The hull rear stowage boxes were modified by omitting the fuel racks and having them open from the op towards the center. Some of these saw the heavy duty suspension units (D47527) with the offset return roller on a straight arm bracket.
The last M7 built had the heavy duty suspension as standard along with the sharply angled transmission armor, lowered pulpit, lowered headlight mounts, and modified engine deck which omitted two vents to either side of the center deck plate.