The T84 8in Howitzer Motor Carriage was the first attempt to mount a heavy artillery gun on the chassis of the M26 Pershing tank, but only two pilots were ever built.
Early in 1944 work began on the 155mm Gun Motor Carriage T83, which carried a 155m gun on the chassis of the Medium Tank M4A3 (this later became the M40 Gun Motor Carriage). In April 1944 the Artillery Board suggested mounting an 8in howitzer on the same chassis. Army Service Forces approved the idea as long as the heavier T26E1 chassis was used instead. Two pilots of the T84 were ordered, but construction was delayed by the limited availability of the T26 chassis. Trials were underway at the end of the war, and the project was then cancelled. As a result of the delays the M4A3 was eventually used to carry the 8in Howitzer, as the M43 8in Howitzer Motor Carriage (T89), which saw service during the Korean War.
The T84 used the basis chassis of the T26E1, with six road wheels on each side. The T84 reversed the layout of the Pershing. The engine and transmission were moved to the front. The drive wheel was also at the front. The old engine compartment was removed and an un-armoured open fighting platform was built at the back of the vehicle. The main weapon had a limited range of traverse, which all came from the existing 8in howitzer mount.
The T84 was developed alongside two heavier motor carriages, the T92 240mm Howitzer Motor Carriage and the T93 8in Gun Motor Carriage, but these both involved a much larger rebuild of the basic Pershing.
Armament: 8in howitzer