The M37 is a very similar design to the 105mm HMC M7. The lighter-weight chassis of the M24 tank was expected to be more useful and easier to handle than the HMCs based on medium tanks. The M4 howitzer was ballistically identical to the M2A1 howitzer found in the M7, but had been designed for use in the Sherman tank. The lengthened Chaffee chassis of the M37 featured more distance between the road wheels. The driver's hatch remained in the usual place, and the steering assembly access hatch remained from the M24 tank as well. Just behind the driver's hatch is the external fire extinguisher control handle, and stowage for the maching gun tripod is visible on the front plate of the fighting compartment to the driver's left. Top cover brackets run along the top of the side armor, and stowage for top cover bows is visible on each side of the fighting compartment.
Horizontal grab handles are welded to the side of the superstructure, and the rear stowage racks are folded down on this vehicle. A fourth track return roller was necessary with the lengthened chassis.
The howitzer travel lock is folded down onto the vehicle's front plate, and the machine gun mount dominates the vehicle's right front corner.
The rear stowage racks are secured on this vehicle. The hinge for the rear door can be seen. When swung down to the open position, this door could also be used as a loading platform. Below the door is the air outlet grille of the engine compartment. Spare track block stowage is on each side of the towing pintle, and the engine exhaust outlets are visible just inboard of the lifting eyes on the hull rear.
This machine is fully stowed, and the driver's hatch is open with a foul-weather hood installed. Note the travel lock for the .50cal machine gun. (Picture from TM 9-2800-1/TO 19-75A-89.)
The rear of the fighting compartment is shown here. The breech of the howitzer can be seen to the left, and the air inlet grilles of the engines are on the right. The panel on top of the air inlet grilles is the radiator cover. Bins for the horizontally-stowed ammunition can be seen to the rear of the fighting compartment sides, and a mount for a portable fire extinguisher can be seen to the front of the image. With the expanded metal floor missing from this vehicle, the location of some of the suspending torsion bars is visible running across the bottom of the fighting compartment.
With the engines and transmissions removed, the transfer unit can be seen at the front of the engine compartment, with a coupling on each side for the separate transmissions. The transfer unit combined the power output of the two engines and provided two forward and one reverse speed ranges; the transmissions themselves did not have a reverse gear. One engine could also be decoupled at the transfer unit. The howitzer mount and machine gun position are visible to the front.