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Newbie Tranny Question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by woodpecker, Mar 6, 2001.

  1. woodpecker

    woodpecker Registered Member

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    Okay, I keep hearing the same terms, but I have no real idea what everyone is talking about.

    Automatic Transmissions: Stall Speed and Lock-Up.
    What do these two terms mean exactly?

    Thanks!
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Stall speed is kinda tricky...basically its what RPM the torque converter will allow the engine to spin up to, without (much) forward momentum..the higher the stall of the converter, the higher the motor revs if you were to hold the brake and gas it. Not really useful unless you are looking for faster off the line acceleration, or have a motor that needs to be in that RPM range to make peak power...basically thats what stall is for, to get the motor to the the desired RPM range quickly...

    You will see other terms associtated with lockup. Converter Clutch, TCC (torque converter clutch) etc. All that means is that the torque converter, under the correct conditions, controlled electrically usually, will "lock up" It basically eliminates the "stall" of the converter. With no stall, the engine would die. Lockup in essence makes the torque converter act like a clutch in a manual transmission vehicle. Reducing power loss due to the built in stall of the torque converter. If a torque converter had 0 stall, or is locked up, the engine will die when you come to a stop. (thats why a car will idle in drive Either would be exactly like taking your foot off the clutch in a manual transmission car at a stop...man, thats a lot of stuff, and probably helped clear that up for you not one bit..sorry.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  3. Blazer79

    Blazer79 1/2 ton status

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    Another way of putting it:

    If the auto tranny was a person driving a manual tranny, the stall speed would be the rpm at which that driver released the clutch in order to take off.

    The torque converter could be seen as two fans facing each other. One has the drive force from the engine, and the other is connected to your driveline. When the engine spins, it's fan "blows" on the driveline's fan, making it move. When you're driving, both fans may or may not be moving at the same speed. A lock-up torque converter, mechanically engage these two "fans" together so they are moving at the same speed, helping you save gas.

    Hope this makes it clearer.

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    <A target="_blank" HREF=http://blazer79.coloradok5.com>http://blazer79.coloradok5.com</A>
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