Troubleshooting - Porsche 928 Workshop Manual

38
Automatic Transmission/Gears, Valve Body
928
a
No upshifts.
Cause/Correction:
1. Check governor pressure. If there is no governor
pressure reading, continue with point 2. If governor
pressure is correct, continue with point 3.
2. Clean and service centrifugal governor.
3. Disassemble and clean shift valve housing. replacing
if necessary.
Condition:
Upshifts only in upper speed range of gears.
1. Check and adjust control pressure cable
2. Check governor pressure and replace centrifugal
governor, if governor pressure is too low.
3. Service control pressure valve
Condition:
Upshifts only in lower speed range of gears.
Cause/Correction:
1. Check whether control pressure cable is disconnected
or torn, and then adjust accurately.
2. Check full throttle stop. Move accelerator pedal from
full throttle and check whether throttle is against
full throttle stop, adjusting if necessary.
3. Check governor pressure and replace centrifugal
governor. if governor pressure is too high.
38. 116 Troubleshooting
Printed in Germany