On Thu, 22 Sep 2005 10:48:07 -0700
Randall wrote: RE: overdrive question
and quoted from my email, (which I had quoted from a friend)
> You could, of course mess around with the pressure
> relief valve to increase the pressure but this will give a very
> rough/abrupt engagement
With respect, Leon, this suggests to me that your friend is confused about
how J-type overdrives work. The pressure relief valve is not in operation
when the overdrive engages, and hence adjusting the valve can have
absolutely no effect on engagement. (Unless you've turned the pressure down
until it won't hold engagement.)
A-type (and D) are of course an entirely different story.
Randall
I put this to my friend in the UK, who has responded thus:
I think I've amassed a reasonable understanding of the workings of the A, D
and J type over the years. The principle difference with the J type is the
operating pressure is constantly present whilst the gearbox mainshaft is
turning
(at sufficient RPM). A and D types only pressurise when the solenoid is
engaged, hence the delay in engagement. The line pressure does have an impact
on
the engagement and how much torque the unit will transmit before potential
problems like slippage occur. The point I was trying to make was that a common
"mod" is to fit an "uprated" PRV usually from a Stag to up the pressure to
approx. 550lbs and I did not necessarily agree this was the way to go. Perhaps
I
should've said this can lead to abrupt engagement if pressure is set too high.
Hopefully that'll put matters straight.
Regards
Leon
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