Shift Lever Position Decoding / Indicators
The 4L80E and 4L60E and their variants have an internal shift lever position sensor that requires the hydraulic pressure from a running engine to work properly. The internal sensor also does not decode park and neutral separately. This internal sensor is unsuitable for neutral safety, reverse lamps, or a lever position indicator. You must use an external sensor on the transmission to drive a gear position indicator. Lokar, GM, and Dakota Digital sells sensors for this purpose.
Shift Lever Position and Engine Braking
The 4L80E and 4L60E and their variants require the shift lever to be moved to the D2 or D1 positions in order to have engine braking / deceleration. The engine braking function can not be actuated by the transmission controller alone without physically moving the shift lever. Some customers have asked about using the Lokar Electronic Sport Shifter on GM 4L60E and GM4L80E transmissions. It is possible to use this lever, but it will leave the driver unable to engage engine braking in the 2nd or 1st gear because the Lokar Sport Shifter does not have D2 or D1 positions.