1981 928 with auto transmission, attempted first transmission fluid replacement in my ownership. Previous fluid looked clean, new even, but I wanted to change it for peace of mind.

Warmed up car, level surface, drained trans pan, drained torque converter. Changed trans filter and pan gasket. New crush washers - 2 large at pan drain plug (above and below banjo fitting), 1 small at torque converter drain plug.

Used transfer pump for new fluid into fill reservoir. I cycled through the gears 5-6 times, for a few seconds each gear and kept refilling. She's taking only about 3 liters total, book says it should take 5.5 liters. Fill reservoir is full, cannot seem to put anymore in. Tranny slips, barely moves the car, assume its because of the low fluid...but how do I get more in?

Help. Advice appreciated.

 

When I did my '81 years ago it seemed to take a long time to get converter oiled again. Also the fluid needs to cycle to radiator and back, maybe air in line?

 

did you start the engine? it should be run and then cycle through the gears a few times and recheck the level.

 

Also is picture of car running or off? When I did mine car was up and idling while filling.

 

Photo is of car when turned off and cold, but I had turned it on/off 5-6 times to cycle through the gears while filling. The fill reservoir would empty out when cycled through the gears, then I would refill. At this point its not taking any more fluid and you can see the fluid level in the photo. Car is on my lift and I don't want to leave it running with just the parking brake on, so I turn it on/off after going through the gears.

This is a painful process. I probably spent 4-5 hours on this task alone and its still not right. Unlike any other auto trans refill I have ever done.

Do I have a trans cooler? I was thinking about some kind of air bubble in the system as a blockage to accepting more fluid...the manual does not talk about that, is there a way to bleed off air?

 

based on your info you may have installed the new filter improperly and or the filter is defective or the wrong filter was installed,
and its not sucking in the new fluid
fill procedure is to fill the pan,
run the engine for about 20 seconds shut it off.
refill the pan run 20 seconds refill ,
and repeat till the fluid stays constant .
it will take about 7 to 9 quarts depending on how much fluid you removed.

once the level is constant then run the engine and cycle through the gears.

At this point top it up run the engine for 20 seconds and see if the fluid drops .

if not then remove the pan and inspect the filter mounting collar for the proper fitment.