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NP241 VSS- convert from mechanical to electric

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supergeess

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This might be a dumb question. I have a 89 NP241 that was originally cable driven speedo output. I needed an electric VSS signal for my 2005 6.0 vortec/4L60E 4X4 conversion. So, I just had the guy who installed my SYE swap out the cable driven output for a used electric VSS he had sitting around. My question is: was there supposed to be a reluctor ring installed along with switching to the electric VSS? My rig runs fine, but sometimes, randomly, doesn't shift properly out of 1st gear. It will run perfect for 2 weeks, then randomly begin not shifting properly. Also, once I drove on a highway and got up to about 55-57MPH and the speedo dropped to 10 and 14 MPH, but he rig was still running fine. Once I got off the highway, it began the shifting issues. I have hooked up a scan tool and get P0719- Brake switch, but when I check everything, there is no problem with the new brake switch, wiring and power. Just rying to get some answers before I start taking things apart. Any help is greatly appreciated.
 
Need a reluctor for the VSS to work. 40 tooth.

I would think that were it not present, you'd have already triggered a code though. VSS is probably even more important that vintage, than it was on the earlier stuff.

Can you see if vehicle speed is being reported to the PCM with the tool you have?
 
Just spoke with the guy who did my SYE on my transfer case and he said that he definitley put the relucter ring on. I'm gonna pull out the VSS and use a mirror to look in the hole to double check tonight.

The only codes I got was P0719 (brake switch) and I checked that and wiring and connections and power supply...everything was good. after erasing this code, it was shifting fine for a couple weeks, then the shifting problem came back, this time with no DTC code. Since I couldn't clear the code, I was not sure of what to do, so I parked it. The next day, I jump in and took it for a ride and it was shifting perfectly and has been for 5 days now.

At this point, if the reluctor ring is in there, I'm thinking it could be a bad ground somewhere or the VSS is bad.
 
At least on the VSS side, don't guess. Put a proper scan tool on it. If the PCM is seeing vehicle speed, there is nothing wrong with the VSS. The improper running speedo is a problem, but if the trucks performance didn't change, and no code was set, I would almost suspect it was a gauge issue. Again, the scan tool would tell you. Do you have cruise? I don't know how your stuff is all wired, but if cruise, and it worked/works, again pointing away from VSS. If the signal from the VSS was dropping out for whatever reason, I'd expect everything tied to VSS to not function properly.

I am certainly not "up" on the LS-series stuff, there has to be a way to monitor the trans as it's running, to see what it's supposed to be doing at what time, and what is actually happening. But I'd also think that if there was a VSS issue, the PCM would be able to "see" the problem with the engine RPM/Trans internal RPM, compared to what it is seeing for road speed, and trigger the CEL.

Not too tough to check for the reluctor I suppose.
 
Thanks for the repsonse. I am also working on getting a scan tool which can live monitor powertain/drivetrain.
 
I have a VSS housing for a 241 I'll sell you if you go that route...pm me if you're interested...


same as the one jeff in co used...


I sold my t.c. I was going to use.
 
Greg Ducato said:
not to hijack the thread but if you want to sell the cable drive components of the 241 I would love to have them :D
Click to expand...


You'll probably find a lot of interest, as cable-driven 241s are much less common, and desireable as replacements/upgrades for older vehicles. Maybe someone will even trade for it.
 
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