‘87 944 2.5 Auto gearbox intermittent
08-12-2018, 09:16 AM
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‘87 944 2.5 Auto gearbox intermittent
Hoping someone has a bright idea I’ve missed.
Having just rebuilt my differential due to ring gear and pinion disintegrating I reinstalled the transmission yesterday and followed the Porsche workshop manual to the letter. Took her for a couple of short test drives including a short run on a motorway and she drove better than ever. Following a short break I then headed out for a longer drive, got less than 5mins from home and lost drive, no noises just no drive. I got recovered home and gave up for the day.
This morning I carried out an ATF check as per the workshop manual, all looked good, halfway between min and max. Headed out for another drive and only made it to the end of my road before loosing drive again. Pulled over, stopped the engine and then restarted less than 1min later, had drive. Got home and she lost drive again before I could get into my garage. Stopped and restarted engine and she drove into the garage. ATF level all looking good.
Any ideas welcome as I’m at a loss!
Having just rebuilt my differential due to ring gear and pinion disintegrating I reinstalled the transmission yesterday and followed the Porsche workshop manual to the letter. Took her for a couple of short test drives including a short run on a motorway and she drove better than ever. Following a short break I then headed out for a longer drive, got less than 5mins from home and lost drive, no noises just no drive. I got recovered home and gave up for the day.
This morning I carried out an ATF check as per the workshop manual, all looked good, halfway between min and max. Headed out for another drive and only made it to the end of my road before loosing drive again. Pulled over, stopped the engine and then restarted less than 1min later, had drive. Got home and she lost drive again before I could get into my garage. Stopped and restarted engine and she drove into the garage. ATF level all looking good.
Any ideas welcome as I’m at a loss!
08-13-2018, 06:53 AM
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I'll start with a big caveat: I don't have experience with a 944 auto, but I do have experience with other autos. With that in mind...
-Do you get drive back after stopping and shifting through all gear positions without turning off the engine?
-Does it shift smoothly between gears? Any lag shifting from park or neutral into drive or reverse?
-Does there seem to be any consistent "cause" ie anything that happened each time right before it loses drive? (upshift, downshift, idle, etc)
-Seems too simple, but.......did you make sure all the electrical connections were solid?
-Do you get drive back after stopping and shifting through all gear positions without turning off the engine?
-Does it shift smoothly between gears? Any lag shifting from park or neutral into drive or reverse?
-Does there seem to be any consistent "cause" ie anything that happened each time right before it loses drive? (upshift, downshift, idle, etc)
-Seems too simple, but.......did you make sure all the electrical connections were solid?
08-13-2018, 01:55 PM
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08-13-2018, 02:00 PM
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I'll start with a big caveat: I don't have experience with a 944 auto, but I do have experience with other autos. With that in mind...
-Do you get drive back after stopping and shifting through all gear positions without turning off the engine?
-Does it shift smoothly between gears? Any lag shifting from park or neutral into drive or reverse?
-Does there seem to be any consistent "cause" ie anything that happened each time right before it loses drive? (upshift, downshift, idle, etc)
-Seems too simple, but.......did you make sure all the electrical connections were solid?
-Do you get drive back after stopping and shifting through all gear positions without turning off the engine?
-Does it shift smoothly between gears? Any lag shifting from park or neutral into drive or reverse?
-Does there seem to be any consistent "cause" ie anything that happened each time right before it loses drive? (upshift, downshift, idle, etc)
-Seems too simple, but.......did you make sure all the electrical connections were solid?
- no, have sat with engine running shifting between gears for up to 5mins no drive comes back, however if I stop engine immediately after losing drive and then restart 10seconds later I have drive.
- no lag shifting into gear and whilst it has drive it shift between gears smoothly, almost unnoticeably.
- haven’t noticed any consistent ‘cause’, just seems to lose drive after a minute or so each time.
- the only electrical connection to the transmission is for the Speedo sensor which goes into the diff. There’s only 2 mechanical cables to the gearbox, 1 from the shifter and 1 from the accelerator pedal.
08-14-2018, 06:20 PM
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Filter is clean, checked before reinstalling transmission.
What is the something that ‘may’ help?
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08-14-2018, 08:46 PM
#8
Internal seals is what goes bad and you loose hydraulic pressure. There are pressure test ports you can check. IMHO I've never really saw the point in those test ports. The good news is that RockAuto has the rebuild kits and they are inexpensive compare to the rest of the 944 stuff. And being a 3 speed automatic they are also easy to rebuild unlike a 5 speed manual.
One last thing to check is being you already had the transmission out is the manual selector shaft adjusted correctly?
One last thing to check is being you already had the transmission out is the manual selector shaft adjusted correctly?
Last edited by marc abrams; 08-14-2018 at 09:07 PM.
