"The Pacific Car and Foundry Company (subsequently PCF Defense Industries) submitted a concept study for a new family of full-tracked armoured self-propelled weapons and was subsequently awarded a contract for the design, development and construction of six prototype vehicles: two 175 mm self-propelled guns designated the T235, three 203 mm (8 in) self-propelled howitzers designated the T236 and one 155 mm self-propelled gun designated the T245.
Major design features included the interchangeability of the 175 mm gun, 8 in howitzer and 155 mm gun in a common mount, on a common chassis; use of the 8 in howitzer and 155 mm gun field pieces and portions of the M17 standard mount; and drastic reductions in size and weight over conventional equipment which was made possible through a new hydraulic lockout system."
Source: http://www.army-guide.com/eng/product1778.html