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Discussion Topic:
Double clutching.
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Gary M. |
05-26-2011 @ 5:30 PM
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Member
Posts: 218
Joined: Oct 2009
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What exactly is double clutching and is it necessary on our old Fords. Mine is a 39 Standard and when I shift its not always smooth. There is a new clutch,preasure plate,throw out bearing etc. The car is all stock. Thanks...
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47Jack |
05-26-2011 @ 5:37 PM
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Member
Posts: 34
Joined: Sep 2010
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Double clutching as I know it is...after starting off with your 1st or 2nd gear depending on which tranny you have, you put in the clutch and shift to neutral, let the clutch out in neutral. Then you put the clutch back in and shift to your next gear. You can double clutch going up in the gears or while shifting down. Hope this helps. Jack
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Gary M. |
05-26-2011 @ 5:55 PM
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Member
Posts: 218
Joined: Oct 2009
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What is the purpose or action of doing this ?
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Stroker |
05-26-2011 @ 5:59 PM
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Senior
Posts: 1460
Joined: Oct 2009
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Gary: Double Clutching is designed to make the input shaft, and it's constant-meshed gears approximate the speed of the gear that you are trying to engage. The older Ford, and heavy-duty Ford truck transmissions did not have synchro-mesh transmissions, so to avoid "grinding, or grating" the gears, this shifting technique was developed. The process involves letting the clutch out after shifting out of one gear, and approximating the needed rpm to allow shifting to the next gear without grating the gears. Downshifting, generally requires letting the clutch out in neutral, and revving the engine up to allow the lower gears to engage smoothly. It's kind of an "art", and all truck transmissions are a little different in their respective technique. Having said that, your 39 should not need to be "double clutched". I have driven a 38 for many years, and while these top-loader Ford transmissions are not quite as sophisticated as a modern Muncie or Borg Warner, they really don't need to be double-clutched. Going from low to second, just wait a second or two before stuffing it in second. My dad used to tell me to just say "synchro-mesh" while passing through neutral, and it would slip into second just fine.
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Gary M. |
05-26-2011 @ 7:22 PM
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Member
Posts: 218
Joined: Oct 2009
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I did notice that giving a little time between shifts made for a smoother shift. Knowing that it is normal makes me feel better . The double clutching does sound a bit complicated. Thanks for the wisdom .....
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supereal |
05-26-2011 @ 7:59 PM
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Senior
Posts: 6819
Joined: Oct 2009
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Dan covered it pretty well.. Two things affect the ability to smoothly shift a non syncro gearbox. Be sure your idle speed is correct, and use 140 weight oil. It slows the cluster down to allow a better mesh speed.
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