Tranny shift points and mystery hose
09-21-2012, 06:22 PM
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Tranny shift points and mystery hose
After reviewing a variety of posts, as well as some helpful insight from some of you, I decided to tackle changing my tranny oil and cooler lines.
Problem: Tranny doesn't slip, but shifts quickly from 1st to 3rd off the line. Not a whole lot of Oomph from standstill in "D" either. Manually shifting is solid. No downshifting once in 3rd at highway speeds.
Action taken: Dropped pan, pulled TC plug,changed filter and gskt as well as the cooler lines which were leaking. Pulled cap off modulator valve and o-ring was intact. No signs of leakage. Checked vacuum lines where I could reach them, everything looked ok.
Results: Found a random vacuum-looking line hanging out by the filler cap, no connection I could see. After re-filling the fluid as per the service manual instructions,
I took it for a spin. No change. There were no filings or signs of damage in the pan or the filter. Talked to a "Porsche Guy" in Edmonton who allegedly knows a bit about 928's, and he suggested that if it isn't vacuum related, it might be an kickdown linkage adjustment thing. The service manual appears to suggest checking stall speeds, but that's not quite in my wheelhouse just yet.
Also, just out of curiosity, what is this electric item her just above the drain plug? Just curious.
Oh yeah, in case it's a part of the diagnosis: Since I got it the car will roll in park. The PO said that he had to fiddle with the shifter just to get it to work. Could it be that
it's not properly engaging the tranny? Like I said, 1-2-3 & R work fine as long as you perform your shifts manually.
Problem: Tranny doesn't slip, but shifts quickly from 1st to 3rd off the line. Not a whole lot of Oomph from standstill in "D" either. Manually shifting is solid. No downshifting once in 3rd at highway speeds.
Action taken: Dropped pan, pulled TC plug,changed filter and gskt as well as the cooler lines which were leaking. Pulled cap off modulator valve and o-ring was intact. No signs of leakage. Checked vacuum lines where I could reach them, everything looked ok.
Results: Found a random vacuum-looking line hanging out by the filler cap, no connection I could see. After re-filling the fluid as per the service manual instructions,
I took it for a spin. No change. There were no filings or signs of damage in the pan or the filter. Talked to a "Porsche Guy" in Edmonton who allegedly knows a bit about 928's, and he suggested that if it isn't vacuum related, it might be an kickdown linkage adjustment thing. The service manual appears to suggest checking stall speeds, but that's not quite in my wheelhouse just yet.
Also, just out of curiosity, what is this electric item her just above the drain plug? Just curious.
Oh yeah, in case it's a part of the diagnosis: Since I got it the car will roll in park. The PO said that he had to fiddle with the shifter just to get it to work. Could it be that
it's not properly engaging the tranny? Like I said, 1-2-3 & R work fine as long as you perform your shifts manually.
09-22-2012, 01:14 AM
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Shift problem sounds like Bowden cable (throttle quadrant to transmission) adjustment - sounds way too loose or even broken/disconnected.
Hose may be from the vent on top of the transmission - I'm not familiar enough with the early cars to know.
Hose may be from the vent on top of the transmission - I'm not familiar enough with the early cars to know.
09-22-2012, 01:33 AM
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Ok, I'll check out that cable. As I said in the initial post, the PO said he fiddled with the shift Linkage, maybe he messed with some other connections/cables as well. The work he claims he did wasn't quite as advertised....
09-22-2012, 01:44 AM
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09-22-2012, 02:09 AM
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Ok, I'II locate and check the bowden cable, Then confirm vacuum, then try upping the pressure On the modulator. Piece of cake......by cake I mean "ahhh- @#!&+". Thanks for the links and ideas.
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09-24-2012, 04:48 PM
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Don't think I have rear AC. Hell, I technically don't have front AC right now.
What about a vent for the rear diff? A it's part of the tranny assy, might it have such a thing?
What about a vent for the rear diff? A it's part of the tranny assy, might it have such a thing?
