John:
That was a really concise explanation of how a torque converter operates. The part that I question is the term "stall speed" being related to the RPM at full throttle, in which the stator begins to spin along with the impeller and turbine. You may very well be correct on this, but I've always heard that term defined as the RPM that the engine will develop at full throttle while the turbine is held stationary. I can see where the stator would start spinning and "getting out of the way" at 30-40 MPH under light throttle in high gear, but if you were at WOT, that would occur at a much higher speed, right? I know that if the something goes wrong with the one-way clutch and the stator stays locked, it can really create a drag much like the brakes being on.
I was with some guys that were hill climbing with 4x4's several years ago and an F-250 would not climb the hill, and it wasn't because of wheel spin. It gradually came to a stop even though he was using WOT in 1st gear. It stalled out and would no longer move up the hill. Wasn't this an example of "stall speed?" Under those conditions, the stator would have been locked and the torque multiplication at max (as well the potential for heat build up.)
Bob
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