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Transmission core

The proportioning valve is bolted to the ABS unit but the ABS not connected won't effect it. All it does is when a major leak happens like a line or hose blown out, it limits fluid to that area and allows pressure to the brakes that are still functioning or holding pressure.

Even though the rears are not functioning, the parking brake can be causing issues or return springs letting the shoes to go against the drum creating a drag. You can feel it by rotating the tires by hand

Backprobing the connector can be done with a multimeter on the ohm setting or "beep" setting. One lead on the connector pin and the other lead using a wire piercing adaptor so you can connect to each wire to each pin. BUT... that method isn't recommended in corrosive environments since you are basically putting a pin hole through wire insulation in an area where the wire can corrode and cause issues later down the road. Ill let Will give you a better method explanation like finding the corresponding pins up at the ECM to ohm test them.
 
@Rockabillyrat
This is where I can’t help people understand how to do basic testing like when we were talking about a voltage drop test. Could you do a 1-2 minute video or maybe pictures with a good yet simple explanation for him?
I have typed, erased and typed like 4 paragraphs trying to explain it. Below is the best I can come up with and not muddy the waters.


@Stoney and everyone else- NEVER pierce the wire insulation. Backprobe is done to not mess up the insulation. Piercing insulation on control circuits can be the cause of millions of nightmares.

on each connector you think he might have messed with:
Using a meter with probe connectors on the end of your meter leads you attach back probes (pic). Some people diy them from small paperclips and alligator clip on the meter lead.

You insert the pin on the BACK SIDE where the wire goes in the connector.
Then the other on the out going pin on the other side.
You can test how good the signal or power is to something while the connector is still in place, or unplug the connector and test each pin in the unit.
my suggestion would be testing with the connector together in this case because the metal pin might have pushed out just a tiny bit from the plastic holder. So on one side of the connector all the pins are good going in, but the other side isn’t in place so it won’t carry the electricity through.


3FB0001A-2C15-4453-808D-0A1F0239E2EC.jpeg

HERE IS PROBES IN CONNECTORS THAT ARE STILL TOGETHER: checking this way that power and ground are both present. If he put the two probes on the two ends of the red wire on opposite sides of the connectors, he could verify the pins are making good contact through the

DB877663-2B03-44E9-ABD7-A863E725292A.jpeg

HERE IS A HOMEMADE PIN OF SOME KIND THAT HE PUTS IN PLACE, THEN USE AN ALLIGATOR CLIP TO ATTACH THE LEAD TO.


6FD69E10-BC94-4314-A1AD-DCB0A10A82D1.jpeg
HERE YOU HAVE TO LOOK CLOSE. Coming out of the end of the green piece is a tiny wire probe going into the back side of the connector.
B2BD6589-9FCB-4762-8C25-883816C3233C.png
 
I am not where i can get my set and make my own pics to demonstrate the difference in single pin probing and through connectors probing. I searched google pics and probably watched 8 horrible YouTube videos each showing as much what not should be done as little portions of what is correct.

Stoney- once you understand what to do you will be like “that’s it?” If i was with you it can be demonstrated in 1 minute how to properly back probe.

knowing when to test for voltage and when to do resistance testing is another thing. But to test if two connector pieces are making good connection you can always disconnect batteries, wait a few minutes then backprobe through the connector using an ohm meter.
 
Ok I think I get what your saying. I'd have to go outside and look but I'm pretty sure they all plug straight into trany not into another harness end so that's one less thing to test.. and since issue happened with both tranny's that tells me the plug on the trany itself isn't the issue it would be the harness side.
 
So basically I'm putting one lead in one side of the plug and other lead in back side of plug in where the wires go in to it. On each pin. I'll have to get my meter out tomorrow and post pic of it so you can tell me which settings to put it on.
 
So I'm assuming that since y'all are telling me all this that yes in fact the electrical can make tranny drag...
Lol. Just thought about that ..Tranny....Drag....
 
I had 4wd not working one time when my wife got the truck stuck in mud in our backyard. Actuator was not working. Somehow I had bent a prong in the plug on the acuator it self. Bent it back and it's been good since. You can search for the thread here.

Your brake work scares me. Probably should seek the help of a pro.
 
Big T said:
I had 4wd not working one time when my wife got the truck stuck in mud in our backyard. Actuator was not working. Somehow I had bent a prong in the plug on the acuator it self. Bent it back and it's been good since. You can search for the thread here.

Your brake work scares me. Probably should seek the help of a pro.
Click to expand...
If I was closer I would hand him over this old 1988 Buick Century Custom. Everything about it works except the drivers side seat belt and the windshield has some bad cracks in it, nothing that obscures vision though.
 
I
Big T said:
I had 4wd not working one time when my wife got the truck stuck in mud in our backyard. Actuator was not working. Somehow I had bent a prong in the plug on the acuator it self. Bent it back and it's been good since. You can search for the thread here.

Your brake work scares me. Probably should seek the help of a pro.
Click to expand...
I'm going to try to check all the plugs today. I'll take and post pics.
As for my brake work. Yeah I know. But nothing I could /can do about it.. I need a new spindle / hub. Nobody can get them.. I called every auto parts store checked RockAuto. They can't even get it on order. Local bone yard don't have one. So I gotta wait till I can find a junk truck that has one.
When back brake line blew I didn't have much choice. Have to drive to parts store to get line. So it was best option. Kinda a catch 22..
 
@Will L. Unfortunately i don't have time to make a video today with it being Easter and all. But I will try to put together a basic meter testing thread soon to help some guys understand how to properly test electrical circuits.

As far as brakes dragging the easiest test is to drive it for a while then touch each rotor/drum and see if one is hot. A thermo gun is really the best way but I understand not everyone has one of those. The one shop I worked for require temp reading on all 4 corners after a brake job to confirm nothing was dragging.

For testing transmission circuits i like to do all my testing at the PCM. I unplug the connector and test all the solenoids by measuring amperage. That way you can test the whole circuit at one time instead of going around unplugging everything, or dropping the pan. Ive seen the internal harness wick transmission fluid into the connector and cause issues. To me this sounds like a torque converter issue, but without being able to drive it its hard to tell for sure. Being an OBD2 truck is should set a code if something is wrong internally.
 
@Rockabillyrat will that method of testing work on a problem that is intermittent. I feel like part of the problem finding the problem is that there's no way of telling when it's going to happen. If it's electrical then I'd assume that sometimes it's getting connection and sometimes it's not. But that's just a theory.
I can say that it does seem to happen alot less when I'm driving on really rainy days.. maybe water is getting someplace and helping a connection? Or could be my imagination.
Other thing I just thought of, when you pull those plugs there's a wax type stuff in there that's really gooey. I was told that it's to seal the plugs to stop water from getting in..when I changed the tranny I had to use a hair dryer to get them hot to unplug them..
When the guy that messed the truck up unplugged one he didn't do that..he just pulled it off. I wonder if when he did that some of the wax got into a plug slot.
I agree with you I don't think it's internal tranny. Because I have same issue even after swapping the tranny. And I installed new torque converter when I changed tranny.. oh somebody had asked me what torque converter I bought so I'm going to post a picture of the stickers to it....
 
Stoney said:
@Rockabillyrat will that method of testing work on a problem that is intermittent. I feel like part of the problem finding the problem is that there's no way of telling when it's going to happen. If it's electrical then I'd assume that sometimes it's getting connection and sometimes it's not. But that's just a theory.
I can say that it does seem to happen alot less when I'm driving on really rainy days.. maybe water is getting someplace and helping a connection? Or could be my imagination.
Other thing I just thought of, when you pull those plugs there's a wax type stuff in there that's really gooey. I was told that it's to seal the plugs to stop water from getting in..when I changed the tranny I had to use a hair dryer to get them hot to unplug them..
When the guy that messed the truck up unplugged one he didn't do that..he just pulled it off. I wonder if when he did that some of the wax got into a plug slot.
I agree with you I don't think it's internal tranny. Because I have same issue even after swapping the tranny. And I installed new torque converter when I changed tranny.. oh somebody had asked me what torque converter I bought so I'm going to post a picture of the stickers to it....
Click to expand...

Intermittent issues are that hardest to diagnose. It's hard to test a circuit if every thing is working at that time. If I run into problems like that I will wiggle wires and sometimes spray electrical connectors with water to see if I can get it to act up. Hell one time I pull the pan and heated the shift solenoids with a heat gun and got one to drop out when it was hot.

Gm used that sealing glue on thoes and ive seen plenty of people damage those connections by removing them without heating them up. I would give those a good look over and make sure he didn't damage them. Look closely at the wires. Sometimes if someone pulls hard enough they can damage the wire internally.

As far as the converter goes im not transmission expert. I can diag them and I've rebuilt a few but I don't know that part of the industry as well as others do. I know the recon converters had a ton of issues. We call them the blue bomber for a reason. THEFERMANATOR might have a better input on the converter you used.
 
Yes doing it like Rockabilly said is the smart move. But only because you saw the mechanic mess with a specific connector and after that is when the problem started-
That is why I would check there.

When you drive and feel the issue and if you can’t decide if it is tranny or brakes-make it a habit to check heat by feeling rim temperature if you don’t have a temp gun. Learn what is “normal” when things are not acting up. Then when it does act up if the heat is the same as normal- not a brake problem. If one or more wheels is hotter than usual- that shows the problem is brakes. If only one wheel then it is at that location. Both fronts or both rears it wont be at the wheels but prop valve, abs or master cylinder.

Something me and my friends here did when there was no money to fix the ride when parts total into a few hundred- we used to be able to find mopeds for cheap here. It sucked but got by long enough to save money in fuel and park the rig a month and save money on car insurance. That saved money made up for the parts needed then everything got rolling again. With spring here and summer coming maybe that might be an option?
 
Out of curiosity. How hard is it to completely delete the abs? Jus assumption but wouldn't it basically be just unhook all lines and install a 't' after it comes off the master cylinder to go to front brakes And direct line from master cylinder to back of truck for rears?? It's unhooked anyway and would eliminator valve issues.
 
Guess I misunderstood.. I thought by running it the old way would eliminate proportioning valve. I don't know anything about them
 
I think the proportioning valve can be separated from the ABS unit and deleted, but you will have to re-plumb the lines. the proportioning valve has ports for both front calipers and one for the rear drums. here is a pic I found online for a basic design. the pressure differential valve is what blocks off fluid to ether front or rear in the event of a pressure loss due to a blown line or hose.
the bleeder rod is a rod that can be pushed in to reset the valve if it's gets tripped in the bleeding process or if a line gets blown.

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