GM 4L60/E transmission Archives - Transmission Digest
Sonnax introduces Smart-Tech clutch kit for GM 4L series

Sonnax has introduced a new Smart-Tech clutch kit for optimizing clutch capacity and guarding against clutch burnup in GM 4L60, 4L60-E, 4L65-E and 4L70-E transmissions. This kit (part no. 77734-01K) includes eight .067-in. BorgWarner high-energy frictions and seven .095-in. Lindered steels recommended for use with Sonnax Smart-Tech input housings.

An easier way to install the center support in GM transmissions

Whether you are working on a 6L45, 50, 80 or 90, installing the center support that houses the L/R and 2-6 Brake clutches into the case can at times be difficult. In the past, I would grab the inside of the assembly with my fingertips on the friction teeth of the 2-6 clutch pack. I’d

Deciphering the alphabet soup of shift feel

The GM 4L60 and 4L60-E transmissions have been around since 1982, so virtually everybody in the industry is familiar with their designs and how they work. However, one thing that still generates numerous technical calls and confusion is the alphabet soup of different letter codes that are stamped on the accumulator valve. What do they

GM 4L60/65/70-E Front Planet to Reaction Shaft Thrust Bearing

This new Sonnax front planet to reaction shaft thrust bearing (#74238-01) is an OE replacement for GM ’07-later 4L60-E, 4L65-E and 4L70-E units.

All Over the Map

Burnt 3-4 clutch packs are notoriously common in the GM 4L60/E family of transmissions. Tech hotlines and internet bulletin boards are often jammed-up with people pleading for help with this 3-4 roasting. Some technicians get frustrated and throw multiple Hail Mary replacement parts at the transmission when facing this issue. But it doesn’t have to be an exercise in frustration; burnt 3-4 clutches can be transformed from a dreaded problem into a routine moneymaker.