Almost immediately after the M4 Sherman was standardized, the US Ordnance Department started work on a successor. Three series of medium tanks were developed, the T20, T22, and T23 where the main difference laid in the chosen transmission. Particularly T22 had Ford GAN V8 engine with M4 type mechanical transmission.
The T22E1 was the T22 re-equipped with the turret originally built for the T20E1, which was armed with a 75mm gun M3 hooked up to an automatic loader. Although this gun featured a phenomenal 20 rounds per minute rate of fire, the technology was not mature enough to work properly and the gun itself was considered inadequate by that time. The project was suspended and then cancelled in February 1944.