Re: [MV] Info on CUCV kickdown switch.

From: Ted Hintopoulos (hint@northnet.org)
Date: Thu Sep 26 2002 - 10:21:03 PDT


Got a few more questions regarding, CUCV kickdown switch.

I was refering to the electrical slide switch that is bolted to the pedal
support plate under the dash. I've not actually tested the tranmission
on the road, but when I slide it down towards the floor, I do
hear the solenoid in the transmission click.
So, there is power and the switch is making electrical contact.
My question is, the pedal shaft barely moves this switch
and there doesn't appear to be an adjustment allowing you to move
this switch. Is there an additional part missing here?

THIS SWITCH ONLY GOES ON WITH "THE PEDAL TO THE METAL".

The variable vacuum control, at the injection pump, generates the varing
vacuum signal that goes to the transmission modulator on the TH400.
This is easy to adjust and the TMs explain it well. I use a hand
operated vacuum pump, one of those brake bleeders for example.
They generate about 20" of vacuum, more than enough.

With the distance block ( .646" thick) between the pump boss
and throttle stop, the valve is rotated so that you see about 8" of vacuum.
The TMs cover this well. Whether the .646 is critical, I really don't think
so.
With a vacuum gauge connected in place of the line that goes to the tranny,
you will see about 10-14" at the idle stop. This drops to about 0"
before full throttle position. The transistion from 10/14 to 0 is what you are
adjusting when you rotate this valve (at the pump).

The valve and the vacuum pump on the engine, just simulates what a gas engine
does. High vacuum when you are idling to low vacuum when the gasser is
"working". This vacuum signal hits the transmission modulator and
varies hydralic pressure and the 1-2 shift points in the tranny.
There is no real vacuum in a diesel so you have this valve and vacuum pump
simulate the vacuum/engine load demands that our TH400 needs.

NOW, BACK TO THE UNDERDASH SWITCH by the "gas" pedal,
there doesn't seem to be any mention in any of the TMs regarding
postioning, adjustment or photos pertaining to it.

(Guess I've hit on an interesting thread)
Ted.



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