Scott's 1972 Chevy K-20. A place to start.

[gerfunken]

...more...

[gerfunken]

...still more...

[Dieselwrencher]

That's what I'm going to do on mine as well when I get to the wiring portion. I actually installed a ford one on there to get the truck to Good Guys this weekend. But will change back to the GM one when I get my wiring harness un-molested.

[ryanroo]

Excellent!

no worries on the flange, im just glad it didnt fall out of that envelope! haha

[Dieselwrencher]

Looks very nice Scott! My first bit of advice, chit can the stock CAD unit and get one of the lok right or similar kits. The stock ones are a PITA to keep working right.

[gerfunken]

Originally Posted by Dieselwrencher

Looks very nice Scott! My first bit of advice, chit can the stock CAD unit and get one of the lok right or similar kits. The stock ones are a PITA to keep working right.

Ryan, thanks for the advise. I have looked at dropping that, and I know that there are currently toe broken vacuum lines in the system that I need to contend with. I really want to, but it isnt in the cards at this point in time. Priorities are to get the truck gunning, come up with a fuel tank solution, paint and interior. After that, I'm going to circle back for a couple of things, like winch, cargo rack, new tires, and a couple of other things that are on the list.

They say that projects are never really done, and I'm living proof at this point my goal, similar to you is together to the Goodguys car show in November, with my two buddies ('62 Ranchero &'69 Bronco). We spend a lot of time helpingeachother out, and our goal. Is to get all 3 vehicles done for the show this year.
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[Dieselwrencher]

Scott, you could build your own and save the money. I wish you luck but you have some time. I missed Des Moines Good Guys for three years with my truck before I got it there. I'd really like to get to the Az Good Guys some day.

[gerfunken]

Originally Posted by Dieselwrencher

Scott, you could build your own and save the money. I wish you luck but you have some time. I missed Des Moines Good Guys for three years with my truck before I got it there. I'd really like to get to the Az Good Guys some day.

Yes, there are possibilities. As far as missing shows, well, let's just say that I'm a slow starter as I've had this truck since 1999, and missed a number of opportunities to show it off. I must say though that I've only had it down for one hunting season in 14 years, which is really more important.

[gerfunken]

So, since I'm tired of loosing links that I've found in the past, I'm going to start posting reference information here as well. As I have basically put an entire 94 Dodge under my body, I end up having questions that I need to find the answers to. Maybe others will also find the information useful:

Today's topic, Dodge's CAD system. LINK

4WD dodge trucks from 94-early 02’ had a CAD system for the front axle. It messes up a lot so here is a rundown on how to track the problems. One alternative is a posi lock cable that allows you to engage the CAD manually, eliminating a lot of problems. http://www.4x4posi-lok.com/

Vacuum Lines

There are 4 vacuum lines that serve a purpose for the CAD. First off is the white or grey line. This line is the supply line for vacuum. It runs from a T connector on the firewall, down to the vacuum switch located on the top of the of transfer case. Secondly is a green line. This line T’s into the transfer case vent (marked in the pic) and also goes to the vacuum switch to serve as the vacuum vent. It runs up to the firewall and has a fancy end on it that keeps dirt out. Then there are the red and black lines that control the actual CAD. I think red is for 2wd and the black controlled 4wd. They go directly from the vacuum switch to the CAD on the axle. They swap vacuum so one will have vacuum and the other will just be vented.

One cause of issues can be the vacuum lines being full of mud. Blow through each one to make sure they are all clear, any connection can be pulled off, there is nothing that is permanent, if it is rubber, it can be pulled.



Vacuum Switch

The switch itself is very simple and merely swaps vacuum between the red and black lines. All 4 lines go onto the big black connector which will pull off of the vacuum switch. Then you will have just the switch and 4 little ½” tubes where the vacuum lines go. To ensure it is working, take the grey line out and make sure it is getting vacuum (truck must be running). Then pull the red and black lines and the red should have vacuum if it is in 2wd and when you put it in 4wd, the vacuum should switch to the black. You can pull each line out of the 5” or so black hose coming out of the switch so you can feel for vacuum there, just remember where each line went. Make sure the big black connector is not full of mud and you might have to take the vacuum switch out by unscrewing it from the transfer case, then look in it and make sure it doesn’t have mud in the 4 ports either. If it does not switch vacuum, it is junk. NAPA has them in stock as they are a common part among vehicles.

CAD Vacuum Solenoid

The solenoid that does the actual 4wd engaging runs by vacuum with a diaphragm that pushes or pulls the axle coupling to engage or disengage 4wd. You can take it off of the truck and hook the vacuum lines up and see if it moves in and out. It should move in and out easily by hand. If it does not move easily by hand and does not move in and out when you switch vacuum (make sure it actually has vacuum at the lines too), then it is junk and must be replaced. NAPA has those too for much cheaper than anyone else. Ebay has them for even cheaper.



4WD Light Switch (Not being used)

The 4WD indicator light you see on your dash is ran by the switch that is in the CAD housing. When the shift fork moves forward into 4wd, the shaft presses the light switch because it is just a push button. If your light doesn’t work you can test the switch with a multimeter set on ohms. Take the electrical connector off and measure resistance. It should go to 0 (or close to it, maybe 0-10ohms) when it is in 4wd and be at infinity (open) when it is 2wd. You can do it in the truck or you can simply unscrew the switch and just press the button by hand. If it does not do that, it is junk. If I remember, this was a dealer only part. (See video at end)

Shifting Fork

The fork is what moves the coupling back and forth and all I wanted to mention here is that there are 2 versions of it. One is for 94-99’ 2500s, and the other is for 2000-early 2002 2500s. 1500s use the same fork but for different years.

Video

Here is showing how to check for solenoid operation and how to replace a bad one. It shows how to test the 4wd light switch. Also shows how the axle coupler works.

Vacuum Line Schematic

[gerfunken]

Ok, looking for a little bit of assistance in trying to figure out the O/D for a 47RH transmission. The only diagram I've really found is this:



What I'm trying to determine is the best way to hook up the transmission so that I can continue to have overdrive. It doesn't feel like I'm understanding what they're documenting in sites like
THIS

From reading the components, it seems that I need to install two A/C switches (one for 44 PSI, one for 52 PSI) on the #4 governor pressure port (upper left in this picture)



It also provides a warning that "The figures on the pressure switch will only be correct if you have a stock tire size and rear end ratio.", so how does this change if I'm running 35" tires (315/75r16)?

I'm kind of lost on this one, and looking for a little bit of help...

[ryanroo]

Originally Posted by gerfunken

Ok, looking for a little bit of assistance in trying to figure out the O/D for a 47RH transmission. The only diagram I've really found is this:



What I'm trying to determine is the best way to hook up the transmission so that I can continue to have overdrive. It doesn't feel like I'm understanding what they're documenting in sites like
THIS

From reading the components, it seems that I need to install two A/C switches (one for 44 PSI, one for 52 PSI) on the #4 governor pressure port (upper left in this picture)



It also provides a warning that "The figures on the pressure switch will only be correct if you have a stock tire size and rear end ratio.", so how does this change if I'm running 35" tires (315/75r16)?

I'm kind of lost on this one, and looking for a little bit of help...

there are more than one ways to hook stuff up. the PATC write up is for a gas engine(thus the use of manifold vacuum) you can just run a toggle for the TCC and OD on the dash and switch them manually when you want either to happen. that would get old.

using the line pressure and a pressure switch is what the PATC write up is about. line pressure in the 47rh is determined by the governor speed therefore your vehicle speed. so a bigger tire will mean you reach 44 mph before you reach 44 psi in line pressure.

you can use the factory dodge ECM and hook it up as it was in the dodge and it will control your shifting in and out of OD as well as the TCC. it will also do your voltage regulation and time out on the grid heaters.

since you dont have a load based source of vacuum, if you eliminate the ECM and use the pressure on the govenor port witch switches, you will have to find a way to switch the TCC off, and OD off when you are under heavy throttle at speed. that would be done i think with the voltage comping out of the TPS, but im not sure how you would set that up. or you can use a micro switch(s) on the throttle linkage somewhere to break the circuit at a certain throttle input so it will kick out of lock up and or OD. im not sure how that would work, as i quit researching after i bailed on the auto.

i am sure Ryan or Nick may have better ideas as they have actually completed this swap before

Ryan

[legendman]

I am going to use switches for a bit then switch to the dodge ecm down the road
I have a 94 ecm that goes with the 47rh I got.

Here is a pic of the pinout on a 95 ecm.

[Dieselwrencher]

The seat is looking great in there! I hear you on the heat. The south bay in our shop is hotter than any Arizona day here when it's 90* minimum. There's no insulation on the bottom side of the tin roof and it is like an oven in there. I need to get that fixed soon.

[gerfunken]

So, I know that a couple of you had commented on this specific picture...



And I realized, that I did really need to get a push rod for the brakes to work properly. So, Monday morning I went down to the nearest pull-a-part to me before work. I found two suitable GM vehicles that used hydroboost brakes, and pulled two different pushrods. Bringing both of them home and comparing the two I realized that they were pretty much identical.

So, that being said, I decided to pour myself a beverage after work today and go about fixing the problem.



mmmmmmmm... tasty

Now, about that pesky push rod....



Let's see if I can put you where you belong...



yes, you'll do nicely....

put it all back together...



Now to find a black sharpie and fix the "need push rod" to "doesn't need push rod"

[gerfunken]

The other thing that I forgot to mention last week was that I was able to hook up the throttle cable. I was able to reuse the Dodge's cable, but had to make a couple of modifications to the gas pedal. The pictures are after-the-fact, but I can provide a brief explanation as to what I did.

Step 1) pull out the pedal assembly.

Step 2) saw from the top down into the open hole (mimicking the way the Dodge's pedal sat.

Step 3) cut the top portion off, about 1/4" down from the flat spot (right below the bend.)

Step 4) on the remaining pedal piece, cut another 1/4" off of the top.

Step 5) rotating the top piece 180 degrees, and resting the flat spot in the bend against the top part of the pedal assembly, weld it back together.

Step 6) (and actually, in between each step so I got it right....) bolt it back in place and test it.

Basically, I was able to move it down about an inch, allowing for full range of motion on the pedal, and covering the full play in the throttle.

Like I said, pictures are garbage, but here they are:

[Dieselwrencher]

Scott, that is very nice! It's kind of ironic you just got this, and last week I picked up a 28 Sport Coupe............... I'm pretty sure this is what yours is too. Mine is just an empty shell though.

[ryanroo]

the difference is... Scotts wife knows about theirs.


BAM!

[gerfunken]

Originally Posted by ryanroo

the difference is... Scotts wife knows about theirs.


BAM!

LOL... my wife made me buy it, I swear!

[6lcummins]

Originally Posted by ryanroo

the difference is... Scotts wife knows about theirs.


BAM!

Hey now, she walked around MY 28 Sport Coupe on sunday and didn't say a thing... Well it's mine if SHE asks lol

[Dieselwrencher]

Originally Posted by 6lcummins

Hey now, she walked around MY 28 Sport Coupe on sunday and didn't say a thing... Well it's mine if SHE asks lol

Yeah, so there half bachelor man.

[ryanroo]

one word.


facebook

[gerfunken]

Originally Posted by Dieselwrencher

Scott, that is very nice! It's kind of ironic you just got this, and last week I picked up a 28 Sport Coupe............... I'm pretty sure this is what yours is too. Mine is just an empty shell though.

Originally Posted by ryanroo

the difference is... Scotts wife knows about theirs.


BAM!

Originally Posted by gerfunken

LOL... my wife made me buy it, I swear!

Originally Posted by 6lcummins

Hey now, she walked around MY 28 Sport Coupe on sunday and didn't say a thing... Well it's mine if SHE asks lol

Originally Posted by Dieselwrencher

Yeah, so there half bachelor man.

Originally Posted by ryanroo

one word.


facebook

Wow, my build thread is being leveraged as a means for hiding new toys from wives as well as veiled threats to rat out that knowledge to aforementioned spouses. This reads like a jealous bromance gone bad.


Hahahahaha
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[ryanroo]

Sorry Scott, we have a tendency to go wildly off track. seems like every thread in the diesel conversions category has a few "off- topic" pages in it... whoops

i cant help that Ryan is jealous of my half- bachelor status...

[gerfunken]

Originally Posted by ryanroo

Sorry Scott, we have a tendency to go wildly off track. seems like every thread in the diesel conversions category has a few "off- topic" pages in it... whoops

i cant help that Ryan is jealous of my half- bachelor status...

no worries... I actually thought it was funny...

[6lcummins]

Originally Posted by ryanroo

one word.


facebook

I ain't skerd

Originally Posted by gerfunken

Wow, my build thread is being leveraged as a means for hiding new toys from wives as well as veiled threats to rat out that knowledge to aforementioned spouses. This reads like a jealous bromance gone bad.


Hahahahaha
Posted via Mobile Device

You should hear the Voxer conversations. It's rather comical

Originally Posted by ryanroo

Sorry Scott, we have a tendency to go wildly off track. seems like every thread in the diesel conversions category has a few "off- topic" pages in it... whoops

i cant help that Ryan is jealous of my half- bachelor status...

It's because we go with the flow and like shiny objects. BTW you're so called "half-bachelor" status still doesn't help you get sh!t done.