How many volts should be going into the VSS on the back of a 4L80E

[MuddiGGEr25]

Another quick update. If I reset the computer I definitely get a 1-2 shift. But I think it goes into protect mode aka 2nd gear only after that. It doesn't shift out of first until 30mph, but it's very noticable lol. Anyways I have to look into relocating the fuel pump because it vapor locked at the gas station bc I mounted it pretty close to the heater core hoses. I let it cool off for about an hour and it started right back up. But my FPR gasket is leaking so I gotta go get a kit for that first bc it leaked and caught on fire..... at the gas station.... at the pump.... not a fun day. Anyway after that I'm gonna find the wires in the harness that are supposed to go to the ALDL connector and the CEL and get my codes now. I know I'm gonna get the 2 codes for the oxygen sensors since my 6.2l exhaust doesn't have them and I don't have the 150 to get bungs and sensors right now. We have enough gas ( maybe) to get to our destination so I can find work.

[Irish_Alley]

whats odd is i have a pcm from a i think 93 k3500 with a 6.5 and 4l80e i was planning on using it for my cummins but never got around to working with it. i dont know if anything from that could help you or not

[Irish_Alley]

also since your attachments talk about "code ??" im going to assume thats an obd1 system obd2 afaik would have a letter in front of it. so we know its no newer than 96. and since they talk about toss and from the other data we have i would think that means its no newer than 93. so it has a date of 91-93

[MuddiGGEr25]

Right now I'm in the process of relocating the fuel pump and filter so it won't get so warm. And hooking up the tachometer so I can see my RPM while driving it

[MuddiGGEr25]

Ok I haven't relocated the fuel pump just yet as its now 93F in the shade, but I did switch the wires on the TOSS just to see if it will act any different. I drove around the park and 3000rpm at around 24 to 27mph, not sure if my speedo is right or not. Gonna get up to 55mph here in about 10 minutes

[Irish_Alley]

you said your trans and wire came from a 95 3500 with a 7.4? how does it have a toss? does it have the 3 plugs or just 2? (minus the main plug)

[MuddiGGEr25]

It has 4 plugs, it was pulled from a running and driving k2500, the only issue they had was trans fluid leaking from a poor weld job on the tcase adapter. I mean it's possible it was a 2wd that was rebuilt and made into a 4x4 but it has the 2 larger plugs and 2 speed sensors on it just like a 2wd transmission.


I got 4200rpm at 55mph and it shifts from 1st to 2nd if I leave the PCM unplugged for a bit before a test drive,

otherwise it appears to start in 2nd gear ( fail safe mode if the PCM is left powered on)  I got to 62mph and my rpm were about 5000.


My shift arm is just long enough to get to 2nd gear on the transmission, and I can make it stay in 2nd if I put the shifter there, but if I put it in 3rd or OD it will only engage 2nd when I press the gas (after the rpms come up to the proper speed)


Since I am on a pretty tight budget and time frame, will either of the following options work: can I toggle the 2-3 solenoid with a toggle switch on the dash to force 3rd gear? Of I don't have 4th or lockup it's not the end of the world but we have to be out of here and on our way to missouri before the park closes tomorrow. Or if I extend that 4l60e shift linkage so that I can reach the position for 1/L and shift up each gear one at a time. Will that work even if the PCM is not getting the correct VSS?

I only have my smartphone do trying to read wiring diagrams on here takes forever but I'm working on a way to get codes. But in any case I'm sure it's going into limp mode

[MuddiGGEr25]

I lied, it's the main plug, then a front speed sensor, a rear speed sensor and the 2 plugs on the PRNDL box/controller

[Irish_Alley]

ok so you dont have a toss just a tiss and vss? other signals you have to have is the tps and rpms, do you have those?

[MuddiGGEr25]

No I have a TOSS AND a TISS. I am supposed to have a np241c on the back of the 4l80E but it's just my np208 with a mechanical speedo.

The 241c that was in the donor truck had the VSS. But I couldnt afford to buy it and then try to convert it to passenger side drop. I will attach a link to some pics on my Facebook that I will make public

And my TOSS obviously is making some kind of signal to the PCM because without it I cannot get into 1st gear no matter what

[Irish_Alley]

you need the vss or something to convert a mechanical cable to electric signal. ive looked into a few TCUs and each one requires the vss, i think the reason 4l60e doesnt require a toss is cause they didnt come out till 94 and 94 is when the 4l80e also lost theirs. i dont think the toss sends the same signal as the vss. (but that wasnt true after doing research) and like i stated before the ecm uses the VSS signal for everything and compares the rpms to the TOSS to know if its in 4lo or not. the TISS and TOSS work together to see how much slip the trans have. if it senses slip it will kick into limp mode

[Irish_Alley]

it does appear the vss and toss have the same output.

[Irish_Alley]

im almost certain i could shift 1st and 2nd without any computer hooked up. but anyway, your wire harness and trans came from the same truck 95. youre saying it has a toss so this contradicts whats in that one book about the toss being eliminated in 94. if you have the plug for a tiss, toss and vss then i would think you have to have each one of those sensors working. if you have the wire harness for a tiss and vss then you could in theory plug the vss plug into the toss and get good results.

[MuddiGGEr25]

https://m.facebook.com/story.php?story_fbid=10211259527576774&id=1016864859

There is all my connections. I do not know if I have the rear speed sensor connected to the VSs wiring or the toss wiring. I spliced the rear speed sensor into the only wiring close enough to be connected ( again due to budget constraints I could not purchase the connector)

What I'm trying to figure out is If I can wire a manual toggle switch on my dash ( only to get us to our destination then purchase a scan tool that can read the data stream) that will manually activate the 2-3 shift solenoid and get it into 3rd gear assuming all other factors stay the same from 2nd gear into 3rd. If I can get 3rd I can roll down the highway without screaming.

Obviously flip the switch off when needing to stop and have the gear selector on 3

[Irish_Alley]

i know its not what your asking but i got a black box cost 230 from jakes performance
http://shop.jakesperformance.com/Manual-Control-Box-for-4L80E-JP-MCB.htm

so its simple to wire up and requires no sensors and it turns the trans into full manual. again i know its not what you were asking but its possible to make the trans work and i think ive read online that you could make your own