1942 Chrysler fluid drive Vacamatic transmission - what's it all for?

[Strictlyballroom]

I have spent an eternity reading all the posts, manuals and the web on this piece of kit as my car was missing various components and had virtually no wiring. I'm still not completely there, which is why I have tabled a couple of questions.

 

However, as crazy as it seems I'm not sure as I know what the function of the diaphragm, solenoid, governor, ignition interrupter switch etc is all for. Is it just for kickdown when you accelerate hard? I have read that someone replaced what I suspect is a lot of the hardware for a simple dashboard switch to do the same thing - although I accept this removes the automation that all the kit can perform when working correctly. Nevertheless, it is a solution for me to at least drive the car and understand better the difference the kickdown will male etc.

 

One of the biggest headaches I have is the carb and the fact the linkage just doesn't engage the throttle kickdown switch - I will be able to fabricate something, but I just haven't got to it yet.

 

The wire on the carb as per the photo where does that go? (the black wire I believe is just an earth wire).

 

The governor (as shown in the other photo) appears to have multiple electrical connections. Is this correct? The terminals at the purple and Blue arrow should they have cables connected to them? I believe they are earth, in which case I think the body of the governor supplies the earth and maybe no cables required.

 

I would appreciate any help?

 

Mike

[Doug&Deb]

You really need a service manual for your car. A good wiring diagram will help. I have the later M6 semi auto trans and your components are slightly different from mine. I know from experience that bad wiring causes problems with the trans. Perhaps someone will have a picture of the wiring that you need.

[uncleaud]

Oldcarbrochers.com. Think I spelled it wrong but they have articles and pictures that explains it well.

[uncleaud]

oldcarbrochures.com correct spelling?

[Strictlyballroom]

I have the manual, and a transmission supplement, but it just doesn't make reference to the carb wiring. Also the wiring diagram shows that the governor has an earth connection, but I need to understand whether that's to the contact as shown in my photo, or whether as the Governor is already earthed it doesn't need another wire.

 

Is someone also able to tell me the overall functions of the vacuum diaphragm etc - is it all just for a kickdown? 

 

Thanks

 

Mike

[wagoneer]

You must go and watch the mtsc videos on the fluid drive transmission. The Vacamatic is the predecessor but the components are essentially the same just using vacuum instead of electrical impulses. 

https://mymopar.com/mtsc-1948-volume-a1-checking-the-hydraulically-operated-transmission/

 

 

https://mymopar.com/mtsc-1948-volume-a-the-hydraulically-operated-transmission/

[Dodgeb4ya]

There are three variations of controls on the M-4 Vacamatic.

The diaphram type is the early version.

Controls on these M-4's sadly are not the same as the later M-5 1946-48 transmissions.

To explain/understand the Vacamatics a 1941-48 Chrysler factory shop manual explains them well and has the wiring diagrams.

 

[Strictlyballroom]

As I say I have a wiring diagram, and it shows the governor having an earth connection, but nowhere does it show whether the connections (see photo above) are wired to earth, or whether the body is just earthed via the transmission body.

 

Does anyone have a photo of the top of their governor?

 

 

Does anyone also have any comment on the whether a dashboard switch could in effect recreate the kickdown function by simply removing the current to the solenoid, and in effect bypassing the diaphragm, solenoid, governor, ignition interrupter switch etc? 

 

[greg g]

[Strictlyballroom]

 

Can anyone tell me whether the contacts marked here with two different colored arrows have wires connected to them?

 

Mike

 

 

[kencombs]

2 hours ago, Strictlyballroom said:

 

Can anyone tell me whether the contacts marked here with two different colored arrows have wires connected to them?

 

Mike

 

 

According to the diagram above, it only has one terminal with three wire on it.  No personal knowledge but that's how it looks to me.

[Strictlyballroom]

Thank you Kencombs - hence the confusion.

 

Hopefully, someone has a photo or experience of wiring one of these babies.

[greg g]

Trying to decipher the role of the governor in relation to the shifting sequence.  It obviously reacts to transmission output revolutions.  But do the points open or close rhe path to ground.  Under normal shifting once a preset output rpm is achieved rhe circuit would be set to allow the upshift with the release of the gas pedal. This release allows rhe solenoid to activate to accomplish the up shift.  Under normal driving, the same trans rpm signal qould allow the downshift upon slowing or stopping.   Under wide open  throttle kickdown conditions, the kickdown, cancels th4 Governors hold in of 5he upper gear, momentarily shorts the coil to allow driveline slack to facilitate the solenoid to drop out the higher and pull in the lower gear.  So does the spin of the governor open or close the points to enable the solenoid? 

[Alex]

At my 1941 Royal looks like this ?