Porsche 928 Workshop Manual page 806

928 Automatic Transmission / Gears, Valve Body
38
Condition: Nu brake shifts from 3rd to 2nd and 2nd tu 1st
Correction: 1. Adjust control pressure cable,
2. Service brake shift piston, replacing shift valve tiousing
if necessary.
Condition: Automatic, unwanted downshifts outside of partial
throttle downshift range, without operation of
kickdown switch
Correction:
l
1. Remove kickdown solenoid valve.
Check O-ring on solenoid valve for damage
2. Check whether kickdown switch sticks in pressed position, re-
placing if necessary.
3. Check whether solenoid valve sticks in open position. re-
placing solenoid valve if necessary.
4. Check movement of control pressure valve, cleaning shift
valve housing and servicing valve if necessary, or re-
placing shift valve housing.
Condition: Poor acceleration when moving off
Correction: 1. Check stall speed.
2. If stall speed drops below specified value by approx. 400
to '700 rpm. one-way clutch in converter is slipping. i?e-
place torque collverter.
Condition: Transmission does not make upshifts
Correction:
1. Check governor pressure and when not correct, clean and
service centrifugal governor. If correct. continue with
point 2.
2. Service master valve in shift valve housing. replacing
shift valve housing if necessary.
Printed inGermany I. 1978
Troubleshooting 38 17