Earlier wheeled carriages for the 3 inch gun had been considered. The first was the previously mentioned T7 which was a modified version of the armored car T13. The second was the 3 inch gun motor carriage TIS which proposed to mount a 3 inch gun on a special Ford, four wheel drive, chassis. Later plans changed the special Ford chassis to a six wheel drive version. However, the project was dropped completely in October 1941 and the two T55 series vehicles were the only wheeled 3 inch gun motor carriages actually constructed.
Tests at Aberdeen Proving Ground revealed that the cross-country mobility of the Cook vehicle was inferior to that of a full track tank destroyer such as the T49 then under test. Both the T55 and the T55E1 were canceled without further production.
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