[Gmecm] Was: Geting rid of electronic transmission.

[Garrett Herning]

Hi Don,

Where I work we make all kinds of equipt to test transmissions and trans 
parts. (Zoom Technology, Inc... anyone in the trans market has probably 
heard of us). At any rate, the force motor is nothing more than a pressure 
regulator for mainline into the valve body... We have a solenoid tester and 
can run either solenoid at multiple frequencies and I've never really seen 
any differece in pressure vs current response between 292.5Hz and 614 Hz... 
all they are doing is PWMing to get an average current to it. All you want 
is the PWM frequency to be much higher than the mechanical response of the 
solenoid so you don't get it buzzing with the frequency. Other than that it 
just sort of regualtes pressure along with the TPS signal (stomp the gas and 
it'll jump mainline up... ease off and it pulls it down)

IMHO I don't see any reason the '94 PCM wounld't run the '96 trans just 
fine. The cleaning pulse is just a quick twitch every so often to keep the 
older force motors from building up dirt and sticking... I guess the new one 
was built better so it couldnt do that... having it do that every so often 
won't hurt it at all.

Hope this helps!

Garrett Herning



>From: Don Sauman <donsauman at cythera.net>
>Reply-To: gmecm at diy-efi.org
>To: gmecm at diy-efi.org
>Subject: [Gmecm] Was: Geting rid of electronic transmission.
>Date: Mon, 06 Mar 2006 12:01:49 +0800
>
>I have been following all of this with some interest.
>
>In the spirit of efi and I guess PCMs, I will probably need to reprogram an 
>OBD-I PCM (Don't really want to deal with OBD-II if I can avoid it) to deal 
>with the changed force motor in the 4L80-E autotrans. Previously it 
>operated at 292.5 Hz level but in 1994 was changed to 614 Hz level.
>
>I have a 1996 trans, and a pre-1994 PCM is being sent to me.
>
>Can someone who is knowledgeable explain how the force motor works (perhaps 
>it is solenoid PWM?) and how the PCM may need to be altered to suit the 
>upgraded force motor. Going back to an earlier force motor is not an option 
>is not an option as the torque signal feed passage is no longer drilled.
>
>Also, according to the ATSG Manual, with the new design force motor, the 
>need for the cleaning cycle is eliminated, so the force motor is no longer 
>pulsed every 10 seconds by the PCM/TCM.
>
>The new force motor (8684216) is applicable to 1994- up 4L80-E, 4L60-E, and 
>4T80-E transmissions.
>
>Cheers
>Don
>
>--
>Don Sauman
>35 Asteroid Way
>Carlisle 6101
>Western Australia
>
>P: 08 9361 0337
>F: 08 9361 0581
>M: 0427 389 547 CDMA
>M: 0413 746 695 GSM
>
>
>
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