This Preliminary Information communication provides information to the technician about vehicles that are equipped with 6L80 Regular Production Option Code (MYC), 6L90 Regular Production Option Code (MYD) or 8L90 Regular Production Option Code (M5U) Automatic Transmission, now have Powertrain Grade Braking. Powertrain grade braking assists when driving on a downhill grade to help maintain desired vehicle speed by using the engine and transmission to slow the vehicle.
