[3] He graduated from Alabama Polytechnic Institute (currently called Auburn) in 1944 with a B. S. degree in mechanical engineering.

[4] Lett joined Chrysler Defense in 1950, and became involved in the design and development of the M48 main battle tank (MBT).

As project engineer, Lett supervised the technical design and coordinated with the Army in the testing and evaluation process.

In 1954, Lett became chief engineer and led the design and development of the Army's next MBT, the M60 tank.

[5] In 1972, the Army began the XM1 tank program, and in June 1973 awarded contracts to General Motors and Chrysler Defense to construct prototype vehicles.