The running gear of the M55 and the 155mm self-propelled gun M53 was based on that of the M46 and M47 tanks. Upgrades to the artillery vehicles eventually encompassed components common to the M48 tank, but the running gear never changed. The three square covers in the front plate are transmission access port covers. The howitzer is stowed in its travel lock, and a machine gun is mounted at the commander's cupola on the turret roof. Air intake louvers are visible on the front slope just inboard of the fender-mounted stowage boxes.
The gunner's exit doors are open on the turret's right side, and stowage mounts for spare track blocks are attached to the front of the turret. The mantlet for the telescope M99 is attached to the ordnance mantlet. A small guard wheel can just be seen between the front drive sprocket and the first road wheel.
The gunner's doors are closed on this vehicle, allowing us a better look at the large lower and small upper pieces. Two air exhaust ducts are present on each side: one above the drive sprocket and one covered by a mesh screen in front of the turret. The recoil spade is in its stowed position. (Picture courtesy Jose Maria Serrano.)
The driver also had a pair of horizontally-split doors on the opposite side of the turret, and his periscopes can be seen on the roof above his doors. Directly behind the driver's doors is the outlet for the turret ventilating blower. (Picture courtesy Jose Maria Serrano.)
The rear air exhaust duct is highlighted here. More details of the suspension can be viewed in this image as well.
This view is peering into the open driver's door on the turret's left side. The driver's seat and wobble stick control common to the M46 and M47 tanks can be seen in the foreground. The main instrument panel is attached to the turret roof. The howitzer mount and its recoil and equilibrator cylinders can be seen behind the driver's seat.
The spade is lowered on this machine, giving us a view of the two turret rear doors, which are hinged on the top and bottom of the turret rear to provide a platform and roof when opened. Between the legs of the spade are two rear stowage compartment access doors. (Picture courtesy Jose Maria Serrano.)
The turret rear doors are open on this vehicle. The stabilization spade is lowered, and the left taillight can be seen just above the fender. The final bumper spring is visible above the trailing idler wheel. Inside the turret, a projectile stowage rack is in the rear corner, and the projectile rammer and spade hoist is centered in the turret opening.
A closer view of the rear turret interior is offered here. The commander's seat can be seen under his cupola.
This angle provides a more expansive shot of the interior. The breech of the howitzer is open, and the commander's and driver's cupolas can be seen in the turret roof. The position of the projectile rammer is right below the breech opening.
The upper turret door and the hoist mounted on its inside is highlighted here.
The reticle for the direct-fire telescope T159E1 is sketched. The cross represented zero range and deflection and was used during boresighting. The vertical range line was numbered in hundreds of yards, and each line and space of the broken horizontal lines represented a deflection of 5 mils. The gunner above is depicted engaging a tank at 1,200 yards (1,100m) with a 5 mil lead. (Picture from FM 6-93 155-mm Gun M53, Self-propelled and 8-inch Howitzer M55, Self-propelled.)
The 8-inch projectile rack is shown on the left, and the 8-inch powder rack is on the right. The key for the projectile rack is: A. Cover, assy. 1. Clip. 2. Pin. 3. Cover. 4. Cover. B. Spring. C. Insert. D. Sleeve. E. Clip. F. Shaft. G. Cover. H. Shaft. J. Cover. K. Shaft. L. Clip. M. Shaft. N. Washer. P. Nut. Q. Handle. R. Bolt. S. Bolt. T. Latch. U. Latch. V. Shaft. W. Bolt. (Picture from ORD 9 SNL G-259 List of All Service Parts of Gun, Self-propelled, Full Tracked: 155-mm, T97 and Howitzer, Self-propelled, Full Tracked: 8-in, T108.)