GMC 1976 ZEO 6083 Maintenance Manual page 463

CHECK "LINE TO DETENT" ORIFICE
IN SPACER PLATE
CHECK DETENT VALVE TRAIN
NO 1-2 UPSHIFT AND/OR DELAYED UPSHIFT
OR 1-2 & 2-3 UPSHIFT-FULL THROTTLE ONLY
NO UPSHIFT
WITH BRAKES APPLIED,
CHECK LINE PRESSURE IN DR. AT 1000 RPM
60-90 PSI
SEE
GOVERNOR-CONTROL
VALVE ASSEMBLY CHECK PROCEDURE
DISCONNECT ELECT. PLUG
FROM TRANS. AND TEST
NORMAL UPSHIFT OCCURS
CHECK AND CORRECT DETENT SWITCH
OR WIRING-CHECK FOR SOLENOID CLICK
ROAD TEST
CHECK TRANS. OIL LEVEL
90-150 PSI
WITH BRAKES APPLIED,
CHECK LINE PRESSURE IN NEUT . AT 1000 RPM
1
CHECK SOLENOID FOR
FUNCTION OR DAMAGE
CHECK MOD. FOR LEAKING
DIAPHRAGM OR BENT NECK
CHECK CASE FOR DAMAGE
OR POROSITY AT MOD. VALVE
No . 1- 2 Upshift
TRANSMISSION 7- 15