[Gmecm] Was: Geting rid of electronic transmission.

[Don Sauman]

Thanks for that Garrett.

We don't see many 4L80Es here in Australia except in private imports 
although for a brief period GMH brought RHD Suburbans but they have 
stopped carrying parts even.

Am I reading you correctly to say that feeding the new force motor with 
the lower frequency will work, or do I need to somehow reprogram to 
pulse at the higher frequency?

Cheers
Don

Garrett Herning wrote:

> 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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>
>
>
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-- 
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