With encounters with German Tiger tanks in Tunisia, tanks crews were wanting a tank with bigger guns than 75 mm and 76 mm. It was hoped that the T26 would be able to battle toe to toe with the Tigers.
A request for 8,000 T25s and T26s with 75 mm and 76 mm guns was rejected.
In March/May 1943 the Ordnance Committee suggested that some of the T23s be fitted with 90 mm guns for testing. This was declined but fitting a 90 mm gun to the T25 and T26 was approved.
The T26 was to have an inch thicker armor and tracks four inches wider than the T25.
An order for 40 T25s and 10 T26s was approved.
The T25 was based on the T23 with a different suspension and turret. The turret was larger to handle the 90 mm T7 gun that sat in a T99 mount. The suspension and tracks were later used on the M4 Mediums.
Abandoning the Electric Transmission
Army Ground Forces rejected the electric transmission as it had way too many hurdles to get it to perform properly. In August 1943 the Ordnance Committee converted the vehicles to torquematic transmissions which eliminated most of the problems.
After it was seen that the M4 medium was inadequate the Armored Forces requested that that the T26E1 get immediate priority with 500 being built and Ordnance recommended that 1,500 be built. However the Army Ground Forces felt that was too many and only authorized 250.
It was shown that the T26E1 didn't have enough room for carrying ammunition and the result was the T26E3. Ordnance wanted the T26E3 to become standardized but the Army Ground Forces didn't agree as they felt it hadn't been tested enough. There was even the request to ship the first 20 T26E3s to Europe but, again, Army Ground Forces refused. However, Ordnance was able to talk the General Staff into shipping 20 of them to Europe where they arrived by the end of January 1945. Finally, at this time, Army Ground Forces declared the T26 battle worthy.
In June 1944 a demonstration of the T26E1 and T26E3 were conducted at the Aberdeen Proving Grounds and Ordnance reclassified them as heavy tanks.