The Toyota GD engine series is a diesel engine produced by Toyota which appeared in 2015. It replaced the Toyota KD engine series as a diesel engine series mainly oriented to body-on-frame vehicles. The GD engine featured Economy with Superior Thermal Efficient Combustion (ESTEC) technology. Toyota claims they have a maximum thermal efficiency of 44 percent, "top class" at the time of introduction. The GD engine series is produced in three countries: in Japan, in Bangalore, India by Toyota Industries Engine India (TIEI), and in Chonburi, Thailand by Siam Toyota Manufacturing (STM).