TransGo 4L60E/4L65E/4L70E Gear Command HD2 Shift Kit

This is TransGo part number TGO4L60E-HD2, the Gear Command HD2 reprogramming kit for the GM 4L60E, 4L65E and 4L70E four-speed automatics, 1993 through 2015. It is a valve body recalibration kit, not a fluid additive: you drop the pan, pull the valve body, and install the supplied valves, springs, spacers, separator plate updates, gaskets, shims and bushings to change how the transmission applies its clutches.

The stock 4L60E family shifts soft on purpose, and that slip is what glazes and burns the 3-4 clutch pack and cooks the forward and 2-4 band clutches over time. This kit raises and cleans up line pressure and quickens the 1-2, 2-3 and 3-4 apply so the clutches lock instead of dragging, which is the single most effective thing you can do to make one of these units live behind more torque. It also addresses the common bore wear and low pressure problems that cause a mushy or flaring 3-4 and TCC shudder.

The HD2 is the full Gear Command version, so it adds true manual control: lever-commanded downshifts from 3rd through 1st, and the ability to hold manual 1st or 2nd gear to any speed or RPM. That makes it a good fit for a tow rig, a plow truck, or a swap where you want to grab and hold a gear without the computer overriding you.

Fits the 4L60E, 4L65E and 4L70E used in Chevrolet and GMC trucks, SUVs, vans, Camaro, Corvette and full-size cars across the 1993-2015 range. It is a bolt-in job for anyone comfortable pulling a valve body; printed step-by-step instructions are included in the kit.