A/T - 4L80-E/4L80-EHD Diagnostic Charts Update

9216chevy07

Number: 91-210-7A

Section: 7A

Date: FEBRUARY 1991

Corporate Bulletin No.: 177107R


Subject:
AUTOMATIC TRANSMISSION DIAGNOSIS CHARTS UPDATED


Model and Year:
1991 C/K, R/V, P AND G TRUCKS WITH
4L80-E/4L80-EHD AUTOMATIC TRANSMISSION


SERVICE UPDATE

BULLETIN COVERS:

HYDRA-MATIC 4L80-E/4L80-EHD Transmission updates occurring after Service Manual printing.


LIGHT DUTY TRUCK SERVICE MANUAL UPDATES:

Automatic Transmission / Diagnosis Information:





Range Reference Chart has been revised. (Figure 1)





Wiring Diagram has been revised. (Figure 2)

Remove Notice under Torque Converter Clutch (TCC) Diagnosis:
Notice says: Do not bench test the TCC Solenoid using an automotive type battery. Accidentally crossed wires will damage the internal diode of the Solenoid. (This notice does not apply to the 4L80-E Transmission.)