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Discussion Starter · #1 ·
Is a VSS type sensor required for a 95 47RH to work correctly? Just getting into the wiring piecing what I have together and I don't have a speed sensor anywhere in my setup. What all is required? I have TPS, engine rpm do I need the boost sensor or coolant temp?

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47rh is hydraulic shift so you don't need the vss. You just need the connections for tc lockup, overdrive, backup lights and neutral safety. I think that's it.

Eugene
 

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Discussion Starter · #3 ·
I know what the connections are on the transmission, but the dodge computer controls it. I was just looking over the wiring diagram for the computer and noticed there's a VSS input. I know these dodges used a VSS and the experience I have with other electronically controlled autos is the computer wants to know the vehicle speed in order to control lockup and overdrive operation.
 

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Discussion Starter · #4 ·
4x4. I have a Ford 205 mated to it.

I'm mainly looking for a heads up as to whether the computer will function without a VSS or if I need to figure one out. If I do need the VSS I have several of the Ford type that plug into the tranny inline with the speedo cable, but I have no idea if on of these would send the appropriate signal to the dodge computer.
 

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Discussion Starter · #7 ·
That's some really good info!

Does it work though? If I followed it right, that system is for a gas engine if they're using a vacuum switch.

I'd love to run the tranny mechanically and eliminate the computer.
 

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Discussion Starter · #8 ·
The only problem I can see with that mechanical setup with pressure switches is there's no hysteresis. I'd be concerned at certain speeds the switches could cause overdrive and lockup to "hunt".

I don't have the time to order those switches (needs to drive by the morning), but with the junk I have laying around I think I can machine an adjustable rate spring balanced piston to act with microswitches as a two stage pressure switch.

We'll see...
 

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Of course it works

I am running that set up in my Cummin Suburban with a 47RH: it is completely automatic with no hunting ever. Anyone can drive it and it was cheap. If I were you I would take the time to order the parts.
 

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ac switches? I guess they'll handle oil since the ac is full of it right? did you find a listing on the different pressures for them? sounds like an idea, I need to get some switches to hook mine up in the next few days.
 

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Discussion Starter · #13 ·
Parts store has books and every AC switch has it's pressures listed. Specifically, you're looking for the low pressure side switches.

I'll be keeing my eye out for adjustable units so they could be tuned to what you want.
 

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Pressure switch

Instead of the A/C switch would it be possible to use a Hobbs switch? If you remove the rubber plug in the end of it you can adjust the pressure up or down as you like. It also come as a N/O , N/C , Common.

http://content.honeywell.com/sensing/hss/hobbscorp/catswitch.asp

click on the low pressure vaccum switchs


Also does anyone know the lenght of a 47RH 4X4 trans? I would like to try it in a full sized Bronco project.
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Discussion Starter · #15 ·
The 47RH 4x4 length is 31 1/2 bell to t-case flange.

The pressure switches I bought are preset, but if you pick the epoxy out of the set screw they're adjustable as well.
 

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Discussion Starter · #16 ·
It works great. thanks for the great advice guys. Looks considerably cleaner than the dodge wiring junk, very easy to hook up and works great.
 

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How does the transmission kick out of O/D, TC lockup if there is no vacuum switch used. everything alse about the install seems pretty simple. I have heard bad things about the 47RH's TC, has anyone used an aftermarket one that they are happy with? Would an aftermarket TC cause different line pressures and affect what pressure ratings of the switchs that i need to buy? thanks guys
 

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The vaccum switch act as a throttle position sensor. Once you decelerate the pressure in transmission drops and the pressure switch cuts out or take out od/tc ground. No more tc lockup and od. This is as I understand it to work.

Eugene
 

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Discussion Starter · #19 ·
I've now found the only way to fly is with the adjustable hobbs switches. You can set exactly what you want the thing to do.

The stock 47RH TC leaves some to be wanted as far as stall speed goes. They are pretty much the same as the stock chevy diesel converters, a bit too high for the cummins. An aftermarket low stall converter solves the problem and works great.

I don't run the 4-3 kickdown BS. For the trouble of getting it to work, it's far easier to just drop the shifter into third when you need a hard throttle 4-3 shift. 3-2 and 2-1 kickdown function perfectly normal, they're controlled hydraulically internally.
 

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I've now found the only way to fly is with the adjustable hobbs switches. You can set exactly what you want the thing to do.

The stock 47RH TC leaves some to be wanted as far as stall speed goes. They are pretty much the same as the stock chevy diesel converters, a bit too high for the cummins. An aftermarket low stall converter solves the problem and works great.

I don't run the 4-3 kickdown BS. For the trouble of getting it to work, it's far easier to just drop the shifter into third when you need a hard throttle 4-3 shift. 3-2 and 2-1 kickdown function perfectly normal, they're controlled hydraulically internally.
where can you get one of these hobbs switches? i saw your discussion earlier on them and it does seem like they would be the best thing for this application. How do you like the transmission, do you tow in OD? what kind of MPG are you getting?
 
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