Hard Shifting Transmission
#2
Rennlist Member
I don't think so.
Check the adjustment of the Bowden cable, should be adjusted so that the coupler drops right onto the ball on the bellcrank without any tension.
Next look at the vacuum line going to the vacuum modulator on the side of the transmission casing. Low/no vacuum here will cause hard shifting. If you have a vacuum gauge of some form, see what vacuum is on that line with the engine idling warm. Should be at or above 18 in/hg. If not, start tracing that line along the torque tube and up to the V of the engine.
Good Luck!
Check the adjustment of the Bowden cable, should be adjusted so that the coupler drops right onto the ball on the bellcrank without any tension.
Next look at the vacuum line going to the vacuum modulator on the side of the transmission casing. Low/no vacuum here will cause hard shifting. If you have a vacuum gauge of some form, see what vacuum is on that line with the engine idling warm. Should be at or above 18 in/hg. If not, start tracing that line along the torque tube and up to the V of the engine.
Good Luck!
#3
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Thread Starter
Join Date: Oct 2010
Location: Memphis, TN 1987 S4
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Thanks for info. I’ll check vacuum line. I was working on vacuum lines to get AC to blow colder. Especially the line connected to heater valve. I think the tranny line connect at that T.
#4
Rennlist Member
It is in the vicinity of heater control valve, but will not share a "tee" with it.
There should be a dedicated hard white vacuum line that makes it way from inside where your A/C controls are, all the way to your heater control valve.
Check out this article for great description of A/C-related vacuum lines w/ pictures (click on "vacuum actuators" link):
https://members.rennlist.com/pirtle/svc.html
-Jason
#5
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Location: Memphis, TN 1987 S4
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Fixed it. While getting vacuum line correct for HVAC, I disconnected one of the line to fuel regulator. I’m assuming this caused the tranny to be unable to maintain pressure. Shifting like butter now! Thanks guys
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Speedtoys (08-10-2023)
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#8
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Bertrand Daoust (08-10-2023)