Re: [MV] Info on CUCV kickdown switch.

From: Nathan Wilkens (nathan.wilkens@asu.edu)
Date: Thu May 16 2002 - 14:43:19 PDT


Ted,
You've touched on a sore issue with me! Although it always seems that I'm
working on my CUCV, there is anything really broken with it. But, the
transmission down-shift is one of the things that is painfully
non-functional. If I lived in a flat country, I'd probably never notice
it - but every time I go into the mountains, I feel the pain of not being
able to down shift...

Here's how it's (supposed) to work. The vacuum pump on the back of the
motor generates a nearly constant vacuum (not perfectly constant, but
close). The vacuum line should run up to the fuel injector pump, and
connect to the injector pumps right side (your left as you face it from the
front). There is an adjustable throttle position sensor located on the
injector pump that is supposed to change the vacuum to initiate the down
shift. From there, the vacuum line goes down to the transmissions vacuum
modulator that senses the vacuum pressure and shifts accordingly.

The problem is this: If the transmission is ever rebuilt, I can nearly
guarantee that they hooked it back up wrong (skipping the fuel injector
position sensor) then adjusted the modulator to make it shift normal (on
flat ground only). The other possibility is that since the throttle
position sensor is easy to adjust (but difficult to adjust correctly) they
probably by-passed it.

The 34 manual shows how to adjust the throttle position sensor, but it
requires a special spacer tool (it may be possible from the diagram in the
34 manual to 'fake' the distance and skip the spacer), it also requires
either a STE/ICE (big $$) or the ability to apply a constant regulated
vacuum on one side of the sensor and the ability to measure the vacuum drop
on the other side (a standard vacuum measuring tool will work for this, but
I haven't figure out how to apply the regulated vacuum on the other side-
maybe I can tweak my vacuum cleaner?)
The alternative is to just guess the adjustment on the modulator and
throttle position sensor and keep trying until it works correctly.

Hope this info was useful, and let the list know if you have success!
Thanks,
Nathan Wilkens

----- Original Message -----
From: "Ted Hintopoulos" <hint@northnet.org>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Thursday, September 26, 2002 6:32 AM
Subject: [MV] Info on CUCV kickdown switch.

>
> I've noticed on several CUCVs that the throttle transmission kickdown
switch,
> doesn't get activated when the pedal is to the metal.
> The shaft barely moves the switch arm, not enough to activate it.
> More interestingly, there appears to be no adjustment for it, slotted
> mounting holes, etc.
>
> None of the MIL TMs make any mention of it except for its removal
> and installation nor does my 84 civi manual.
>
> I know how to make it work, but what did the motorpool do?
> Any ideas anyone?
> Thanks again!
>
> Oh....remember that thread a long while back regarding spacers and long
bolts
> being used for no apparent reason; CUCVs, transfer case crossmember and
> steering gear and I'm sure elsewhere.
> Finally hit me (no not my head, but it would help), the bolt maintains its
> torque
> much longer then a shorter bolt would without the spacer.
> Bolt strech. Whether its really needed or not, I'll not go there.
>
> My $ .000025 worth.
>
> Ted Hintopoulos.
>
>
>
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