Trimatic overdrive

[Dr Terry]

In later transmissions like the 4l60E they lock up the torque converter to give it a so called overdrive. In a lot of autos its not actually an overdrive ratio only a direct drive speed (engine and transmission speed the same)

4L60 & 4L60E both have a 4th gear overdrive (0.7:1 ratio), with 3rd as 1:1. They also have a lockup converter. AFAIK all GM 4, 5 & 6-speed autos are set-up this way.

Dr Terry