B
Badger
Guest
"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Fri, 3 Nov 2006 21:01:15 -0000, "Richard Brookman"
> <[email protected]> enlightened us thusly:
>
> >Yes, the TC will lock up at about 53mph or so, and you can feel the
slight
> >lurch as it does so. But there are also what I call (in my head)
half-gears
> >too. Scenario: you are driving up a hill which becomes progressively
> >steeper as you climb, towing a decent weight behind. You start in
lock-up
> >4th. As the road speed drops below 55-ish, there is a slight rise in
revs
> >as the lock-up drops out. Speed drops further and it changes to 3rd. If
> >you now give the box a bit of help and manually lock it into 3rd,
>
> The box is quite capable of going straight from 4LU to 3rd, if you're
> pushing it a bit harder. I think what you're seeing is converter slip in
> 4th, then you pull the lever in to 3 and it goes down to 3rd.
>
> >the revs
> >rise again. Speed drops again and it changes down - but again, if you
move
> >the lever to "2" the revs will rise again. It's as if there are splitter
> >gears between the proper ratios, like a 3½ gear and a 2½ gear, but which
are
> >chosen by the car, not the driver, if that makes sense.
>
> The torque converter is designed to slip within a certain range, which
> smoothes the gaps between the gears. Autos are typically higher ratios,
but
> the torque converter gives a non-solid variable drive. Some industrial
> things ONLY have a TC, no actual gears at all, but they're usually
operating
> in a more limited range of speeds.
>
>
>
> Especially if driving with a fairly light boot, you'll get this effect.
> There are only 4 actual gears, although converter-lockup feels like a 5th.
And the DII has lock-up in both 3rd and 4th don't forget, giving the
illusion of more gears.
Badger.