Porsche 928 Workshop Manual page 793

9 28 Automaric Transmission / Gears, Valve Body
38
ATF level in transmission will change wirh iluid
remperarure.
Max.
and min. marks on rrannparenr
tank are in reference to an ATF temperature of
80" C/116" F. When ATF temperarure is 20 I"
3@" C/68 - 86" F, the ATF level will be 30 mm/
1 3/16 in. below minimum mark (see figure). The
amount of ATF berween min. and max. marks
is 0. 2 liters/C;. 1.5 fluid ounces.
,
i. "'TFj.
,,., >..
t
-I
,"
I = max. at 80" C/116' F ATF temperarure
2 = min. ar 80"
C/116"
F ATF remperature
3 = max. at 20 to 30' C/68 - 86' F ATF-
temperature
After correcting ATF level to specifications,
"perare brake pedal, leave selector lever in each
posirion (R - N - D - N - R) several seconds and
then return ir LO "N". IO that working pistons of
power pans are filled with ATF. Recheck and.
if necessary. correct ATF level.
C - Stall Speed
This check provides informarion on operation of
engine. converter and rransmission. It is applied.
when rap speed cannot be reached or acceleration
is insufficienr.
During this check all the engine power is convened
into heat in the converter. which is why this check
must nor last longer than 5 seconds.
Rear wheels mu%! not be permitted to turn for rhis
check.
Also engine must be at operating remperarure and
develop its full power.
Add ATF to correct level. Cleanliness is essential!
If ATF level is to" low, oil pump will draw in
air, which can be heard. ATF will foam and
cause incorrecr readings when checking ATF
level. Stop engine unril ATF foam disappears
(approx. 2 minutes). Add ATF and recheck ATF
level.
Excessive ATF must be drained or drawn off.
since orherwise traxmission componenrs would
splash excessively and raise the remperarure
to" much, until finally foamed oil is forced out
through vent. This condition could damage
transmission on a longterm basis.
Extra equipment. e. g. compressor for air condi-
tioning, musk be turned off.
Check musr nor be made wirh car's tachometer.
1. Connect tachometer thar ir can be read from
driver's sear.
2. Run engine at about 2000 rpm approx. 2 minutes
prior to resring.
3. Apply parking brake all the way and depress
brake pedal with left foot.
Printed inGermany - 11, 1979
Checking Transmission Operation 38 - 3