Mabel is a 1943 WC-52 that will be restored to a WC-55 configuration, as used by the US Marine Corps in the Pacific on Bougainville.
The difference between the two is not much just a 37mm cannon.
The WC-52 nomenclature establishes that she is a 3/4 ton dodge 4 wheel drive truck with a winch. In this configuration she is intended as a troop carrier and light cargo truck.
However at the beginning of WW2 the military decided that they needed an quick anti tank gun platform that could quickly and easily maneuver to ambush german tanks. The M6 gun motor carriage was created (they tried to mount a 37mm cannon on a jeep but the little go devil was just not big enough to work.)
The M6 gun motor carriage mounts a 37mm M3 cannon in the back (where the troops would sit), and had a special mount on the frame to adsorb the shock from the recoil. It was mounted with combat wheels (that had extra thick rubber walls so they could "run flat" if they were damaged. It was also outfitted with different brackets to allow for the cleaning pole, the bucket, the shovel, pick and axe that would normally be found in the pioneer tools rack, and special ammo cans and weapons holders for the crew. It was then dubbed the WC-55 configuration as this is how these special mounts would be ordered from dodge when it was building the trucks.
When the M6 hit North Africa in operation Torch, it was found to be a very unsuccessful design. The 37mm was not big enough to damage the german light tanks and just bounced off the medium and heavy tanks (such as the Tiger I). The idea was quickly retired and replaced by half track mounted 105mm which worked splendidly.
But the design turned out not to be entirely useless. In the pacific the USMC needed a light quick gun motor carriage that would not get bogged down on the beaches. The M6 GMC turned out to be just what they needed.
3 companies were formed and immediately put to use on Bougainville. The little 37mm gun truck turned out to be highly successful against both the dug in Japanese and their tanks. So the US Army Olive Drab was exchanged for USMC forest green and trucks like Mabel went to work.
So far it has been just under three years since the project began. I am at this point putting on the finishing touches and waiting for her 37mm replica to be manufactured. This should happen before the end of 2013.
Some original photos of M6 GMC WC-55s (I did not take these and assume copyright exists with the US military in some way shape or form.)
This is a prototype shot
Here is another prototype shot
From Italy (???)
In North Africa