241 vss ???
 

I have a 5.3/4l60 out of a 2005 truck with a 241 t/c out of a 91 suburban with vss.I am wanting to wire up the vss and the 4 w/d so the pcm knows when its in 4-low,think thats right.Have the wires from the original harness pulled back to the trans.All of this is going in a 69 k-10.The connector on the wire harness and vss are different.Will the vss out of the 05 t/c work since its the same connector or match up the connector to the 241 vss and how to wire up the 4w/d signal wire...Thanks all Rodney

Re: 241 vss ???
 

Do you know what the pulse output of the VSS on the transfer case is? If you can find that, you can find if the signal will work for the ECM. You may be able to swap the gear on the vss to make the correct signal. The 4l60e was 40ppm, with a 40 tooth gear.

Re: 241 vss ???
 

I'm not sure what the pulse output is on the t/c might have to do some looking and see if I can find it.

Re: 241 vss ???
 

The '91 burb used an A/C VSS sender with 40 pulses per output shaft revolution which is exactly the same signal that the 2005 electronics expects to see.

The air gap between the sensor tip and the reluctor on the output shaft is critical. So, even if the '05 sender screws into the '91 transfer case, it will need to be the right length (and I have no idea how close they are in length). I think you're best bet would be to swap the pigtail on your harness to one that will plug into the '91 VSS. You can buy them from a "good" parts store. Standard Motor Products part # HP3835 and it's about $5.

Re: 241 vss ???
 

Thanks dayj1 I will try to find the pigtail around here,if not I see that i can order it from several places.Do you have any info on hooking up the 4 wheel drive switch on the transfer case as well.

Re: 241 vss ???
 

The PCM signal wire for 4wd needs to be grounded when you're in 4wd (hi or low) and open (not connected) in 2wd. It can be done with a switch on the transfer case shift lever its self or even a toggle switch mounted remotely.

If the line isn't switched correctly the shift points are way off.

Re: 241 vss ???
 

Correction: I can't edit the post above, but the signal wire to the PCM only needs to be grounded in 4 wheel low (not grounded in 4 wheel hi or 2WD).

Re: 241 vss ???
 

I thought that was what I had read that it needed a signal for 4 low for it to shift right,just need to find a switch for it now.

Re: 241 vss ???
 

subscribed

Re: 241 vss ???
 

OK. so to revive an older thread....
I have a question regarding the VSS on a np241 out of a 91 suburban like hozeman469. Since the TC came from a 1991-4L60 and the 2008 package 4.8 and a 4L60E will the stock VSS work? I am not sure of the pulse rate. The 1991 VSS Part #12215001 19K 0
I ordered the 2008 VSS 12376520 and they don't have the same size mounting tread, they are different. So unless I drill out and re-tap the 2008 VSS will not work.

On the shift lever area their is a switch that controlled a light on the dash for 4x4...I am not sure if it reads or senses when its in 4x4 hi and low or just low. I will check it out tonight.
All black is the 2008 VSS, the grey one is the one off of the 1991 NP241C TC

Re: 241 vss ???
 

I also did some research into the 4x4 indicator switch on the TC it reads 4x4 no matter if it is 4 high or 4 low. The only way the indicator on the TC will work is to take apart the TC and cut a notch in the arm where it comes into contact with the indicator switch or put a switch in the shiftier basket so when the gear shift is in the 4 low position it contacts a switch to tell the ECM it is in 4 low.

Does that sound right????

Re: 241 vss ???
 

Anyone have an answer for this???

Re: 241 vss ???
 

Looks like somebody would throw something out there.I haven't found anything for mine yet either.Still looking for a good way to mount a switch.Been working on other things on it have to get back on that before long.Anybody have any ideas???

Re: 241 vss ???
 

Both the sensors in your picture appear to be 2 wire. That indicates that they both output an A/C sine wave which is what the Gen III/IV ECM needs. The number of pulses that is generated is determined by the reluctor ring on the output shaft in the transfer case and not the sensor its self (the sensor just reads the teeth on the ring). Just for reference, the other type of VSS that outputs a DC square wave is a 3 wire sensor.

My only LS swap into a 4WD was a Jeep Wrangler, but I used a NP231C transfer case out of an S10 and it had a 40 tooth reluctor. So, I suspect that the 241 TC has the 40 tooth ring as well. It's really a moot point as the tune can be modified to change the number of pulses per driveshaft revolution to match whatever you have.

What you mentioned about the 4 lo switch is accurate. From my experience, the shift points get really screwed up if the PCM doesn't know that you're in lo range.

Re: 241 vss ???
 

The old VSS will work, All GM 2 wire VSS sensors are functionally the same.
A 4/lo switch can be easily made with a nitrous micro switch that gets engaged by the shifter/linkage.

Re: 241 vss ???
 

Your info is correct from all the research I have found. My plan was to do exactly what you mentioned a micro switch on the shifter housing since it has an actual dish or pan that mounts in/on the hi hump trans cover. Their should be no problem to do so....
Thanks all for the info.

Re: 241 vss ???
 

Or while you have the TC apart you can just grind down a little of the shifting fork inside to only push on the switch when in 4wd low. I might have tried that but I already rebuilt my TC and I am not going to tear it down to do it now!!!!

Re: 241 vss ???
 

I'm a little lost on this 4 wheel drive switch. There's 2 wires that come out. Ones a ground and the other is what?

Re: 241 vss ???
 

The 4WD switch is just that it is a ground switch like the brake switch under the dash. When is 4wd it is pressed to close the circuit and supply a ground to a light!
I have it ground a light on the dash to tell me the truck is in 4WD. I am almost done with mine I can post a picture when I am finished.

Re: 241 vss ???
 

Do I need to have it hooked up? I read were they said the shift points get a little screwy

Re: 241 vss ???
 

sorry I am not sure your drive train..... too many builds I look at....

If you are running a LS swap then the ECM need to know if your in 4Low or not as that changes shift points. The problem is the current 4wd switch just closes on 4wd not just 4 Low. For my swap I am going to have to put a micro switch on the shifter to close when in 4Low.

Re: 241 vss ???
 

Lol ooops so I'm running a 5.3 4L60E with a 91 np241. I got the vss wired but didn't see anything for that switch

Re: 241 vss ???
 

ok so your original 4wd truck harness should of had a plug in the same loom area as the VSS wiring which is for the 4 low indicator. That is the plug that needs to have the circuit closed in 4 Low. Some have said you need it and some have said you don't.... I believe you do!

Re: 241 vss ???
 

Re: 241 vss ???
 

Thanx First C10 I will look more into this. my harness is a 2001. I don't remember there being one but I'm most likely wrong. but your info defiantly points me in the right direction