92 K2500 Revival

[Supercharged111]

I never yanked the sway bar to remove the front diff in the dually or my 1500. Someone's pulling your leg there. Now the center link does get in the way of the front diff, but you just pop it off of the steering box to get your wiggle room there.

 

[Komet]

I never yanked the sway bar to remove the front diff in the dually or my 1500. Someone's pulling your leg there. Now the center link does get in the way of the front diff, but you just pop it off of the steering box to get your wiggle room there.

Yeah, it's probably possible to leave it in, but you do get more room to swing the axles around with it out.

I did end up disconnecting the tie rods so I could move the center link. The chopped power steering line gushed fluid all over my headlight harness when I spun the wheel, so I won't need to lubricate those wires in the future. Anyway, I got the front differential in and everything back together:

You must be registered for see images attach

I took a closer look at the electrical situation, the connectors that came with the truck don't plug into the diff. Right now I'm thinking what the truck was wired for is a thermal actuator and I have an electric actuator. Dorman has a conversion harness available, I'm trying to find the schematics in the '99 service manual to see if I can just splice it over but it's not as easy to navigate as the '92 one.

 

[Orpedcrow]

I won't need to lubricate those wires in the future.

I believe there was a TSB that came out, stating dex/merc power steering fluid was now an acceptable replacement for blinker fluid. Hahah

You’ve really taken on a heckuva task with this un-conversion conversion!

 

[Komet]

Content warning: digicals.

Big thanks to @yevgenievich for doing a lot of the heavy lifting about this conversion. The Dorman harness would have done the job for me, but it's $50 because it comes with a spacer for converting the length of the Electric Actuator to match the Thermal Actuator which I didn't need as my diff is natively electric, and I also already had the pigtail so a lot of the convenience of their harness isn't useful to me. I started by finding a pinout for the plug:

You must be registered for see images attach

Then I tested the actuator to confirm the wires were doing what I thought they were doing:

You must be registered for see images attach

The Dorman instructions from here were also crucial:

4WD Actuator Redneck Fix

$50 is mighty steep for some wire and connectors. Does anyone know the wiring schematics for the dorman 600-600? I already have all the connectors and plenty of wire.

www.gmt400.com

I had an idea of what I needed to do from this post:

convert 1997 chevy 4wd to electric actuator with toggle switch

on my 97 z71 with thermal 4wd actuator i'd like to convert to electric...i have an electric actuator and pigtail from a boneyard...i can machine the spacer ...the electric actuator has a 5 wire plug (only 4 are used)..a brown wire...black wire...black with white stripe wire and grey with white...

www.gmt400.com

So then I took a bunch of notes:

Thermal Actuator function:

4wd fuse sends +12v on BRN to Transfer Case Switch when IGN is ON.

Transfer Case Switch allows +12v on LT BLU when 4wd is demanded from the lever.

LT BLU sends +12v to Thermal Actuator, which deploys the pushrod to engage the front diff. Pushrod auto detracts from lack of thermal energy when LT BLU stops sending power.
BLK is a permanent ground for Thermal Actuator.

Electric Actuator function:

The Electric Actuator is different in that it cannot function without electricity. That is, it will not auto detract the pushrod when power is simply removed. This is why the Dorman conversion harness requires a splice because you need to add a source of +12v when IGN is ON. More on this in a minute. The pinout from the factory is as follows:

A - BLK/WHT - PCM communication, idk I don't have one.
B - GRY/BLK - Ground trigger
C - BRN - Constant +12v
D - unused
E - BLK - Constant ground

When +12v is applied to BRN and BLK is grounded, grounding GRY/BLK causes the motor to deploy the pushrod. Ungrounding GRY/BLK causes the motor to retract the pushrod.

So, we have two problems to solve in order to adapt the harnesses:

1. We need to add a source of constant +12v so the motor can run in and out.
2. LT BLU can be used as a +12v trigger, but we have no ground trigger.

Problem 1 is easy to solve. Do what Dorman does and splice BRN to the BRN wire that sends +12v to the Transfer Case Switch. Motor has accessible +12v whenever IGN is ON, and it's on the 4wd fuse which makes sense.

Problem 2 could be solved with a relay, but there is a more elegant solution. As it turns out, unused pin D is in fact a +12v trigger. It deploys the pushrod in the same way as pin B, except we can use our existing LT BLU wire to control it. So, I depinned BLK/WHT on A using a needle and stuck it into D. The modified pinout is now:

A - unused
B - GRY/BLK - Ground trigger (unused)
C - BRN - Constant +12v
D - BLK/WHT - +12v trigger
E - BLK - Constant ground

With the wires doing what I wanted, it was as easy as attaching a 3 row weatherpack connector to the Electric Actuator pigtail and depinning the factory harness and converting it to a weatherpack 3 row unit:

You must be registered for see images attach

Didn't even need to put new connectors on the factory wires:

You must be registered for see images attach

I verified continuity on BRN so my splice is good. Boom, handled.

 

[Komet]

I keep on thinking I'm ready to drop the motor in, and I keep on finding ways to block myself from doing that. I want to minimize the amount of time it's sitting outside with exposed manifold ports, so I have decided to tackle my hose and fluid transfer assemblies to see what obnoxious problems I've created for myself.

I have the engine and trans assembled:

You must be registered for see images attach

There's a splice in each of my heater hoses, so I wanted to replace them while the heater core connectors are easily accessible. The inlet is 3/4" and every other connection is 5/8", so I'm going to reuse one of the reduction splices I have and run fresh 5/8" line everywhere else. No big deal there.

Power steering hoses need some minor conversion and I haven't decided how I'm going to go about it:

You must be registered for see images attach

The high pressure hose appears to be a direct fit, hopefully that doesn't leak but it's not a big deal to change out later if it does. The low pressure line with cool frame rail cooler was snipped at the rubber line. I could delete it and use the non-cooled return line from the green truck, but I want the cooler. I'm thinking a barbed splice and some fresh return hose will be adequate, although less than ideal since it creates a leak point. I could cut it back to the hard line, flare the end, adapt to -AN, and then leave the hose open on the other side for the return connection but that seems complicated just to avoid one splice.

Oil cooler lines I bought new, so I thought I was good there. Then I had a look at them in the package, and one end is a quick disconnect push fitting. Wtf! I checked what I ordered, new hoses for a '99 K1500, but I definitely unscrewed the old hoses from both ends. Turns out I unscrewed the Oil Cooler Line Connectors from the filter housing, left them attached to the old hoses, and threw the old hoses away. Whoops. That's a $25 mistake, but at least I can get the connectors.

The trans cooler situation is the most complicated. I have a nice big cooler that came on the black truck, and a banana edition little cooler that came on the green truck:

You must be registered for see images attach

Obviously, the big one is what I want to go with, but the connectors are totally different. The small one has what appears to be 3/8" quick disconnect adapters that matches the ends on my hoses. The big one has some abominable thread size between 3/8" and 1/2" NPT. It takes a fitting that is 19mm, smaller than the ends of the oil cooler to radiator connection (20mm), but it's the same type:

You must be registered for see images attach

Anybody know what those are called? I need to figure out how to adapt that to quick disconnect, -AN, inverted flare, anything but a stupid stub. It's possible that's not what's even supposed to go in there, and it was attacked with a grinder until it did. It does thread in though.

Radiator out to aux cooler in hose is also mangled:

You must be registered for see images attach

The rebuilders of the green truck decided that was fine. Almost guaranteed that's the original line that got bent in the crash. won't be using it like that, but could potentially salvage most of it depending on how I need to adapt to the large cooler.

 

[Orpedcrow]

I'm thinking a barbed splice and some fresh return hose will be adequate, although less than ideal since it creates a leak point.

You must be registered for see images attach

I added an inline filter like this one when I replaced my return hose. It has a wire mesh screen and magnets in it. I don’t know if it’s advantageous to have one, but at least you’d have an excuse for the splice lol

 

[HotWheelsBurban]

You must be registered for see images attach

I added an inline filter like this one when I replaced my return hose. It has a wire mesh screen and magnets in it. I don’t know if it’s advantageous to have one, but at least you’d have an excuse for the splice lol

Sounds like a good thing to have, especially on a hydro boost equipped truck. How much is this?

 

[Orpedcrow]

Sounds like a good thing to have, especially on a hydro boost equipped truck. How much is this?

The one at NAPA is $40! I’m sure I didn’t spend that much at Orielly, of course, I was working there at the time lol

 

[Komet]

I added an inline filter like this one when I replaced my return hose. It has a wire mesh screen and magnets in it. I don’t know if it’s advantageous to have one, but at least you’d have an excuse for the splice lol

Hmm, I'm willing to give a PS filter a shot. Gotta fill up that Summit cart to get free shipping anyway. Looks like the options are between $20-$40 for a simple in line kit, with the $30-$40 options looking more robust.

My search for an adapter was long and tedious. I measured over and over, with 3/4"-18 ultimately being the best match for the threads. Pretty much all you can get in that size is inverted flare tube nuts, Aeroquip makes a PTFE hose end adapter for it but it's $30 each. Pretty steep for something that might not work.

I got on the path of threaded bushing reducers, but there's nothing that converts a straight thread pitch to NPT. Then I popped an extra 1/4" NPT to -6AN fitting into the fittings I had, and it fit in. It occurred to me I already have two reducers.

The hole is sixty thou oversize and you can tell by the way that it is:

You must be registered for see images attach

But it threads in there right good. I figure an excessive amount of thread sealant combined with a classic overtorque should work. I mean, it looks good when you're not thinking about it:

You must be registered for see images attach

Time to order some more fittings.

 

[Orpedcrow]

Hmm, I'm willing to give a PS filter a shot. Gotta fill up that Summit cart to get free shipping anyway

That Edelman unit they have looks nice. I might order it next time I have the steering system open.

Here’s mine, easy to service in place.

You must be registered for see images attach