You likely had one of two reactions when you read "4L60E." It was either a slight shrug as you vaguely remembered that you had a 4L60E in your reliable, daily-driven ...

A few months back we detailed the buildup and testing of our street 4L60E trans with help from our trans man Jimmy Galante and parts from Sonnax and TCI Automotive. But that was only half the battle.

The 4L60E is the latest in a long line of durable, high-function GM overdrive automatics that have come our way since the 1960s. The TH350 three-speed automatic had long been a mainstay with Chevy ...