Porsche 928 Workshop Manual page 111

928 Automatic Transmission/Gears, Valve Body
38
Condition:
-
Invisible oil loss (leak cannot be seen on outside) in conjunction with smoke in exhaust.
Cause/Correction:
Diaphragm in vacuum box is defective. ATF drawn in
by engine via vacuum line.
1. Replace vacuum box.
Condition:
Oil lost between torque converter and primary pump
(oil escaping through vent grid).
Cause/Correction:
1. Install oil drain plug on torque converter with a
new seal as well as Hylomar on threads, and
tighten. If still leaking, continue with point 2.
2. Replace radial oil seal and O-ring of primary
pump, inspecting O-ring groove in primary pump
for porous spots. Replace primary pump,
if necessary.
Printed in Germany VIII, 1984
Troubleshooting
38. 121