I am going to be pushing it just to get the transmission in.
CK5
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I must be to old to do this.
I have been reading tech articles and a few forum post trying to figure out how to make this 4l80e work.
The conflicting info is nauseating. Reading at 2am because I can not sleep does not help.
I need to be able to wire it for manual shift. I have found conflicting info on how to do this. It is the early, pre 96 transmission.
I am putting the transfer case back on it because I will not have the time to pull the entire transmission apart to swap the output. This will also give me a VSS output. I can not find what the input voltage is supposed to be. It looks like 5v, but I can not verify that from something I trust. This will also give me the opportunity to add cruise control.
So any real world input would be appreciated.
I have been reading tech articles and a few forum post trying to figure out how to make this 4l80e work.
The conflicting info is nauseating. Reading at 2am because I can not sleep does not help.
I need to be able to wire it for manual shift. I have found conflicting info on how to do this. It is the early, pre 96 transmission.
I am putting the transfer case back on it because I will not have the time to pull the entire transmission apart to swap the output. This will also give me a VSS output. I can not find what the input voltage is supposed to be. It looks like 5v, but I can not verify that from something I trust. This will also give me the opportunity to add cruise control.
So any real world input would be appreciated.
All modern sensors take 5v .
Been so long but thinking the vss makes its own signal . . . But go look up an electric spedo kit for wiring it up for sure .
Been so long but thinking the vss makes its own signal . . . But go look up an electric spedo kit for wiring it up for sure .
Looking at aftermarket speedometer gauges, they have a 5v output.
Not sure if these will help.
Voltage is not listed. Even the diagnostic stuff from GM does no list the output volts for the VSS to check it. After reading more at 3am this morning, 5 volts seems to be the magic number.
I'm not sure what you mean by output voltage? Like the voltage that the VSS is creating?
CIRCUIT DESCRIPTION
The speed sensor circuit consists of a magnetic induction type sensor, a Vehicle Speed Signal (VSS) buffer module, 4WD low switch (when needed), and wiring. Gear teeth pressed onto the output shaft induces an alternating voltage into the sensor. This signal is transmitted to the VSS buffer module. The VSS buffer module compensates for various final drive ratios. The VSS buffer module will also convert the AC VSS signal into a 40 Pulse Per Revolution (PPR) DC signal on CKT 437 to indicate transmission output speed. On 4WD vehicles, the 4WD low signal will also be used for adjustment of the 40 pulse per revolution signal to the PCM
Step 3 says to check voltage across VSS wires and it should increase above 7 volts with drive speed above 10 mph.
CIRCUIT DESCRIPTION
The speed sensor circuit consists of a magnetic induction type sensor, a Vehicle Speed Signal (VSS) buffer module, 4WD low switch (when needed), and wiring. Gear teeth pressed onto the output shaft induces an alternating voltage into the sensor. This signal is transmitted to the VSS buffer module. The VSS buffer module compensates for various final drive ratios. The VSS buffer module will also convert the AC VSS signal into a 40 Pulse Per Revolution (PPR) DC signal on CKT 437 to indicate transmission output speed. On 4WD vehicles, the 4WD low signal will also be used for adjustment of the 40 pulse per revolution signal to the PCM
Step 3 says to check voltage across VSS wires and it should increase above 7 volts with drive speed above 10 mph.
The PCM output to the buffer module. Your info shows 5v from PCM. I will buy an aftermarket buffer module. They do not list power needed. I have a couple of calls in. They all assume using an aftermarket harness like HOWE with the PCM. I am trying to bypass that.
Eddie sent me some info for the manual shift, but it still requires tearing the transmission down for manual shift to plug some ports and open others up.
Eddie sent me some info for the manual shift, but it still requires tearing the transmission down for manual shift to plug some ports and open others up.
I'm not sure. Kinda confusing. Closest truck I have here is a '95 light duty 3/4 ton. I'm not sure what Trans it has but I could pin it out if that vss buffer isn't too hard to get to.
@folkenheath didn't you mention something about manually running a 4l80e in a thread recently?
@folkenheath didn't you mention something about manually running a 4l80e in a thread recently?
You don't have to tear it down, you can wire it for manual shift. I will see if I can find hte diagram I wrote 12 years ago to do this, I did it to my own trans for a while.
In fact, if you just unplug the entire trans connector entirely, it should still have neutral, park, reverse, and 2nd gear when in D. If that doesn't work, something is mechanically wrong with it, because that is the default mechanical/hydraulic result with zero electronics, to get you home.
In fact, if you just unplug the entire trans connector entirely, it should still have neutral, park, reverse, and 2nd gear when in D. If that doesn't work, something is mechanically wrong with it, because that is the default mechanical/hydraulic result with zero electronics, to get you home.
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@ktmoutfront did you ever get to know Alex while you were in CO? He's friends with several CK5 guys including @ZooMad75 and @Larry. He road with @miniwally at Blazer Bash this past year. I feel like he would have the information you need as well if you can contact him.
A lot of articles talk about letting the high pressure bypass so as to not blow out seals. Maybe they are just being too cautious. If you can find that, I would appreciate it.
Wrenchhead. Yep. My first wheeling trip in Colorado when he a Brigham both broke on the same rock. He and his then girl friend/wife rode with me in 07 at Blazer Bash. I did not think to hit him up also.
I think I am to the point of wiring it from the outside, the high pressure be damned.
Another would be Stephen at ORD.
I drove my car for probably 6 or 7 years wired for full manual, never had a problem. Now I have been controlling it with the Holley for a few years without a problem thus far. My brother drove his C10 that way for nearly 10 years, he's finally getting a Holley. Although I expect after over 10 years of abuse, especially now that I am putting over 1000 HP through it at times, its going to need new frictions somewhere in the near future.
I think if a seal blows, it was going out anyway.
I think if a seal blows, it was going out anyway.
I might look at bumping the pressures up on mine. I was afraid to run it too close to the upper limit.
I’m sure @Greg Ducato would be able to shed some light. The article I sent was showing a couple tricks on the pump to lower reverse pressure and reduce pressure on the front seal. I would assume with no electronics, the pwm solenoid would be default to full pump pressure?
That’s promising
Yes, with no electronics it defaults to full pressure.
Unless you have a boost valve leak or some other issue, GM didn't design it to fail under the pressure it creates itself. That doesn't mean it never will.
Both of our trans had been rebuilt by me (my brother was there too for his) before we ran them full manual, that means new seals, bushings, steels, frictions, boost valve, all electronics, internal harness, etc. Plus a few mods. I also put some hardened shafts and stuff in mine as I knew the intended abuse eventually.
After that we wired them externally to shift full manual with the shifter. The PSM is used to control the solenoids, so you essentially just loop the PSM outputs back into the solenoid inputs. It works fine. I even drew up a way to switch them manually with 2 - 4 switches at one point, but I can't find it. Then you would leave it in D, and shift it with switches.
I derived this method by studying the ATSG manual, you can see what outputs the PSM has in different manual valve positions, and what solenoids are on in each gear, and wire it accordingly. It doesn't directly tell you how to do that, but its easy enough to figure it out if you look at the diagrams.
Unless you have a boost valve leak or some other issue, GM didn't design it to fail under the pressure it creates itself. That doesn't mean it never will.
Both of our trans had been rebuilt by me (my brother was there too for his) before we ran them full manual, that means new seals, bushings, steels, frictions, boost valve, all electronics, internal harness, etc. Plus a few mods. I also put some hardened shafts and stuff in mine as I knew the intended abuse eventually.
After that we wired them externally to shift full manual with the shifter. The PSM is used to control the solenoids, so you essentially just loop the PSM outputs back into the solenoid inputs. It works fine. I even drew up a way to switch them manually with 2 - 4 switches at one point, but I can't find it. Then you would leave it in D, and shift it with switches.
I derived this method by studying the ATSG manual, you can see what outputs the PSM has in different manual valve positions, and what solenoids are on in each gear, and wire it accordingly. It doesn't directly tell you how to do that, but its easy enough to figure it out if you look at the diagrams.
As for the speed sensor, I did use the VSS to drive an autometer speedometer. 2 wire VSS sensors are not the same as the 3 wire position sensors such as cam and crank. The position sensors have a seperate power, ground, and signal so they should be correct when stopped, hence the position, not just the speed. Many 2 wire sensors generate their own signal based on the alternating pulses spinning near it.
Some are pulled up or down with ground or Voltage as well I would guess.
What truckman posted goes into more detail. I am just trying to point out the differences. I used to work for a company that sold cam and crank sensors to GM and Chrysler as the on site engineer to test those things back in the day.
Some are pulled up or down with ground or Voltage as well I would guess.
What truckman posted goes into more detail. I am just trying to point out the differences. I used to work for a company that sold cam and crank sensors to GM and Chrysler as the on site engineer to test those things back in the day.
I created a pdf of what to do to wire it for full manual.
Perhaps I will put this in a new thread somewhere so its easier for people to find. I might also link it on my website.
I had sent Dave a way to wire it to shift with push buttons(or rocker switches) years ago, he is seeing if he still has it, I can't find it. If people are interested I can recreate that too if we can't find it. With that way, you would put it in drive, and then shift with buttons electronically. You would leave all switches off for reverse.
With a double pole double throw switch added, you could have both manual shifting with the shifter and push button shifting with the buttons.
Perhaps I will put this in a new thread somewhere so its easier for people to find. I might also link it on my website.
I had sent Dave a way to wire it to shift with push buttons(or rocker switches) years ago, he is seeing if he still has it, I can't find it. If people are interested I can recreate that too if we can't find it. With that way, you would put it in drive, and then shift with buttons electronically. You would leave all switches off for reverse.
With a double pole double throw switch added, you could have both manual shifting with the shifter and push button shifting with the buttons.
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