42/46RH pressure switch piping dilemma

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67dartgtgo

67dartgtgo

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I’m working on getting my 46rh ready as well but I have a question on piping up the pressure switches. Do the OD and LU switches need to be grounded to the transmission through the pressure port piping? I hope I’m saying this right. If I use brass fittings to pipe my pressure switches and use thread sealant is that ok? Are npt brass fitting threads self sealing? Just wondering because the pressure switch needs the ground wire attached to complete the circuit to activate the solenoid, correct? So does the switch base need to be grounded to the transmission case? I’ve ground the truck mount boss off the case for added room.
Mock up pics for your enjoyment...lol.
Any pictures would be greatly appreciated.

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67dartgtgo said:
I’m working on getting my 46rh ready as well but I have a question on piping up the pressure switches. Do the OD and LU switches need to be grounded to the transmission through the pressure port piping? I hope I’m saying this right. If I use brass fittings to pipe my pressure switches and use thread sealant is that ok? Are npt brass fitting threads self sealing? Just wondering because the pressure switch needs the ground wire attached to complete the circuit to activate the solenoid, correct? So does the switch base need to be grounded to the transmission case? I’ve ground the truck mount boss off the case for added room.
Mock up pics for your enjoyment...lol.
Any pictures would be greatly appreciated.

View attachment 1715389548 View attachment 1715389549
Click to expand...

The ground for the solenoids in the trans grond through pins 1&3 on the connector.
The center pin is 12v when the key is turned on.
No, the switches don't need a ground as they are only a switch that the voltage passes through via the terminals.
I do have a suggestion though.
Maybe run a tube from your 90 on the trans up the back of the transmission and mount the switches on the back of your intake. (If your switches are adjustable you'll be glad you did.)
All that stuff hanging down there on the trans is going to cause problems.
If not from vibration, then objects hitting it. (Think a section of truck tire bouncing through under there and then you are spewing trans fluid. (which is highly flammable by the way.


Also on the wiring for the switches they can run from the connector on the trans forward and up instead of back and down.
You can use switches inside the car to manually turn off OD and/or lockup by breaking thier grounds.

Thread sealer on all npt fittings is a real good idea.

I used relays to ground the solenoids and then the expensive adjustable switches to tell the relays when to activate.
This takes the load off those switches.
Number 4 in the pic is a vacuum switch to kick out of lockup under heavy throttle.
It just cuts the ground to the lockup relay when intake vacuum drops to a certain amount. (It's also adjustable, so you can set how much throttle it takes to drop lockup out.

42RH.jpg


OD&Lockup.jpg
 
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Trailbeast, you should make up a kit for this, or at least please draw out an electrical schematic, and fluid schematic of this setup along with a comprehensive parts list for the rest of us wanting to do this. After that the mods need to make it a sticky. I will be doing a 42RH and no several others that want to do this same thing.
 
Thanks TrailBeast. I’ve read everything you have here on this I think and I’ve got the same switch’s including the vacuum. All adjustable and have considered running everything to the engine compartment but want to avoid adding more items in there. I have a lift so switch adjustment is no issue for me. I’d love to your wiring diagram though. I’m sure it would be a giant help.
I was under the impression you only need one wire, ground from the 3 pin, to each solenoid switch as per the PATC diagram and instructions. I noticed you have 2 wires running to/from your switches. Does the circuit have to be complete to ground at the switch?
I admit I don’t know crap about wiring this kind of thing so any help is appreciated.
PATC 727 to 518 / 46RH Conversion Kit. Click here for 727 to 46RH swap wiring diagram
upload_2019-9-5_7-45-50.jpeg
 
67dartgtgo said:
Thanks TrailBeast. I’ve read everything you have here on this I think and I’ve got the same switch’s including the vacuum. All adjustable and have considered running everything to the engine compartment but want to avoid adding more items in there. I have a lift so switch adjustment is no issue for me. I’d love to your wiring diagram though. I’m sure it would be a giant help.
I was under the impression you only need one wire, ground from the 3 pin, to each solenoid switch as per the PATC diagram and instructions. I noticed you have 2 wires running to/from your switches. Does the circuit have to be complete to ground at the switch?
I admit I don’t know crap about wiring this kind of thing so any help is appreciated.
PATC 727 to 518 / 46RH Conversion Kit. Click here for 727 to 46RH swap wiring diagram
View attachment 1715389636
Click to expand...

In your picture where it says "Nothing goes here" is not the case.
Those two terminals each go to a ground to activate the solenoids inside the trans when your adjustable pressure switches close.
(They always have 12v, but need a ground to activate them.)

My ground for those are switches inside the cabin that lets me disable OD and/or lockup by turning one or both switches off.
The pressure switches are disabled when the switches inside the cabin are off.
They still switch with governor pressure, but they cant activate the solenoids inside the trans because their ground is off via the relay, via the manual switches inside the cabin.

In reality, since my solenoids are controlled with relays the ground is cut by the relay when the switches inside the cabin are turned off, or the vacuum switch breaks the ground that activates the relay to activate the solenoids.

Not confusing at all, right?:D
 
Make a nice schematic of your setup people can follow. I'm one of em that would make a copy of that and archive it.

I have heavy duty aircraft toggle switches I can use. I would imagine since those are designed for 28V they can handle 12V without the use of a relay.
 
Please make a schematic. i would like to do this and I'm really confused on how to wire it even more so when you add relays and switches.
 
Yep. Also a parts list of everything. I have no problem picking this stuff up a little at a time to build my own kit.
 
moparmat2000 said:
Also will this setup work with a 42RH? That's the trans we will be using.
Click to expand...

It works exactly the same for all the RH series.
It would take me hours to go back and find all the part numbers and sizes of everything and draw a wiring diagram, and I am currently just not up to it, sorry.
I may work on it little bit at a time once winter actually hits and I'm stuck in the house most of the day.
 
Please do when you have time. I have nothing but time right now as it will be awhile before this trans gets rebuilt and installed. The car needs everything
 
moparmat2000 said:
Maybe trailbeast can verify this so I can archive this.
Click to expand...

That would work.
The one major difference between my setup and that diagram is the grounds of the two #30 terminals on the relays go into the cabin and through two rocker switches on my shifter base and then to ground.
That lets me turn OD and/or lockup off manually if I want the trans to act like the basic 3 speed.
Right now I am in the process of drastically changing rear gears from 2:73 to 3:55, so I am going to have to readjust the pressure switches.
If I didn't have adjustable switches I couldn't make these adjustments to compensate for the lower gearing.

ShifterArt.jpg
 
Trailbeast I think I can make this setup work along with your switches. What was the PNs# of your adjustable pressure switches, relays, and manifold vacuum switch that you used? I would like to acquire these parts for my project, I can figure out the plumbing part of it on my own.
 
moparmat2000 said:
Trailbeast I think I can make this setup work along with your switches. What was the PNs# of your adjustable pressure switches, relays, and manifold vacuum switch that you used? I would like to acquire these parts for my project, I can figure out the plumbing part of it on my own.
Click to expand...

See, that's part of the problem.
I saved all the packaging for the parts used but they are packed away somewhere in my car related stuff because I had to pack it all up in boxes to do the entire house in new flooring.
I do remember that the adjustable switches were from NX Express and were 30-70lb adjustable.
This of course relates to 30-70mph approximately.
They were hard to find until I finally found them there.

One thing I can tell you to make your speed adjustments easier, is once it's all installed set your OD and lockup switches as high as they can go.
Then with both OD and lockup turned on test drive as you back down the OD switch until it comes in at the desired speed.
Then do the same with lockup so it comes on a little higher in mph than OD.
This makes sure lockup and OD are not coming on in reverse order.

Just for FYI note that OD will not engage until the trans is in 3rd because both use the same oil to engage.
This means if you are in 2nd and going faster than the OD speed is set for on the adjustable switch the trans will immediately go into OD as soon as it shifts into 3rd.
Not a normal occurance, but just so you know that's what it will do.
 
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So are your switches set as #4 is O/D and #5 is lockup or is it reversed ?

I am going to get all this written down so I can make up a kit for when it's time for us to do this.
 
moparmat2000 said:
So are your switches set as #4 is O/D and #5 is lockup or is it reversed ?

I am going to get all this written down so I can make up a kit for when it's time for us to do this.
Click to expand...

Yes, 4 is OD and 5 is lockup.
There wasn't room for the word on the shifter base so I went with numbers.

In post 2 you will see 4 black lines on one of the switches, so I don't forget which one is which when I want to adjust one or the other.:D
 
Found these 25-60 psi adjustable pressure switches. Read another post you had saying you found 30-70 psi adjustable pressure switches. How much difference is that extra 10psi gonna make? Also found PN for the vacuum switch you posted in another thread. All I need is a relay PN.

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