Roadstar01

NP246 with TCCM donor from a 2001 GMC Sierra and a Front diff from a 2003 Chevy S10 ZR2 donor. Yes there is a Auto 4WD button but I am not holding my breath that it will ever work, i just have to get the $H and 4L to play nice with this swap

TY for this information, I have been chasing other rabbits and now with winter approaching back to getting this 4x4 worked out. I think you are onto something. I am going to connect to and use the front differential electric lock switch on the front differential from a donor S10 ZR2. I will run one wire from the vacuum actuator relay to the front lock switch and the other from the lock switch to the PCM but still trying to be sure it is red C2 #16 or #19. I had been looking at the 1695 circuit but I see you are thinking 1694 is the answer? The NP246 transfer case and the TCCM is from a donor 2001 GMC Sierra. The front diff is from a donor 2003 Chevy S10 ZR2. What is happening is I hear the transfer case enter into 4WD and more noticeably into 4WD Low. Also the vacuum actuator sucks in and pulls the cable at the front differential. But, when I push the 4WD High or Low or Auto 4WD the Van's check/service AWD light light illuminates and no 4WD. So I missed the boat somewhere and I am thinking this is it. Here is the latest example of chasing rabbits: right now the van is having an updated/improved rear differential work done on the weak 7.5 rear end. I am having an Eaton Truetrac Differential 912A317 and a replacement Motive Gear 4.10 because well it was bang up a bit when the stock differential came apart. Also updating cover by installing a Proform 66667 Perfect Launch aluminum differential cover with Bearing Cap Stabilizer bolts. I sure hope that these improvements make the 7.25" stand up better to be occasionally beat on.

To no surprise, I am finding a conflict in diagrams from different sources. The one you sent me is the 1st time I seen that PIN 19/1695 was for a different TC model. Not say it was not written in the other hundreds of diagrams I have sifted through. At my age I can look right at something and not see it. Called Olditis I think

TY so much for looking into this. Not finding many to engage with me on this. Here is the one line NP246 TC wire diagram and I marked those areas to look at at it relates to circuit 1694, I landed the grey/Black wire on C2 #16 and TCCM F7 4WD Low circuit 1694. The second attachment hopefully is the PCM pinout for a 2001 Sierra/Silverado etc. Please look specifically at the C2/Red colored pin out and pin #19 is specifically for circuit 1695. Also pin 16 is 1694. I wish I could find the PCM wire diagrams showing specifically the PCM interface with the TCCM and front actuator and Transfer case. NP246 Wire Diag .docx C1 and C2 PCM Pinouts for 2001 Chevy Silverado.docx

Here is my 2 cents, Depends on how much you beat on it will be a huge factor. A good rule of thumb is if just normal City driving with no/minimum towing and no rock crawling lol,,, change it every 18 mos but if you do beat on it i would say every 12 mos. Also if you do change out the fluid regularly you will not have to buy the top shelf brand names fluids. Just synthetic is good to stay with

makes 2 of us. but when "everything" is 100% it runs hard. unfortunately all my pain and suffering is self inflicted,, i can't leave well enough alone, call it school of hard knock,, maybe my dad was onto something haha

The LS swap happened a couple years back, and i figured why stop there, as if that was not a large enough headache, so more self inflicted pain,,, hey let's get 4WD Low capability to help pull loads out of the bottom of hills. So now having a cast iron cased front diff with a truck Transfer case. now just have one last thing to complete and that is fool the PCM, transfer case and control module to believe there is a OEM front 4 wire differential actuator motor at the end of the circuits BLK/Whit wire 1695 and light blue wire 1296.

I wish the answer was simple. I am using the 4 button control panel from donor truck, do not believe the NP246 TC is of the Autotrac family. Would be nice to wire in the Auto 4WD button capability but the more I read the more I see Chevy/GM did no favors in the design of A4WD and often causes a catastrophic loss to the the 4x4 system. So I have swapped a NP246 Transfer Case and TCC Module and associated wiring from a 2001 Chevy Silverado donor. The front differential is from a 2003 ZR2 Chevy S10 which uses a Vacuum Actuator and is installed. I have the vacuum electric solenoid connected to the 3 of the 4 wires meant for the Silverado front diff. The wires I am using so far from the Silverado front actuator motor which is successfully triggering the S10 front differential vacuum solenoid are: Brown = ignition 12v, Black = Ground, Light blue is a signal wire which I used for the ground signal on a relay which is closing the relay to send 12 volts to the electric solenoid when put in 4WD. The wire I am not using "yet" is the Black and white 1695 circuit wire. Everything worked great until my Check AWD service light came on and now the front diff is not receiving power from the Transfer case. The encoder motor is still working and 4H, 4L, 2H and Neutral is still online. So without a complete 1695 circuit, I now assume the clutch pack in the TC is not locking up to send the torque through front drive shaft to differential. Also the Safari has a V8 swap and using a 2001 Chevy Tahoe PCM. Clear as Mud?

Yes indeed 1695 is the circuit. I just need to know the routing of that circuit. I have the Black/ White stripe wire located at the Front Actuator as one the 4 wire connections and it appears to be coming from the Transfer Case Control Module Pin E14 which is addressed as 4WD WHL Lock and is part of 1695 Circuit. However on the PCM C2/Red connector there is no Black/WHT Stripe wire landed on Pin 19 which is also 1695 circuit. Where does that leg too the PCM pin originate from or land too? Update... What I found when doing research on the 1695/Blk and wht stripe wire at actuator and this is why I need to get the #19 PIN connected to complete the circuit for this system to perform: On a 2001 Chevy Silverado, a black and white signal wire will typically receive 12 volts when the front actuator is engaged, signifying that the front axle is now in four-wheel drive mode, meaning the front wheels are actively powered. • Signal Wire Function: This black and white wire acts as a "switch" signal, sending voltage to the vehicle's computer when the actuator is activated, allowing it to display the appropriate information on the dashboard (like a 4WD light) and potentially adjust other vehicle systems accordingly. • Voltage Indication: When the wire receives 12 volts, it means the actuator has engaged, and the front axle is now connected to the drivetrain, enabling four-wheel drive.

Can anyone tell me where the black and white stripe wire that is supposed to be assigned to PCM C2/red connector pin number 19 goes to or comes from? I cannot find a spaghetti one line diagram for the PCM for either C1 or C2 connectors. Thank you for any help you can provide.

I recently installed and wired in a NP246 Transfer Case from a 2002 Chevy Silverado donor. I quickly found that the OEM AWD front diff on my 2001 GMC Safari would not allow for smooth turning because the front passenger axle was always active. I went ahead and pulled a front diff from a 2003 Chevy S10. After researching this component I found that it runs off a vacuum actuator to lock in the passenger side axle on command when 4x4 is called for . Now I'm in the middle of wiring it in. As you may know the Silverado has a 4-pin connector for the front differential encoder motor which the S10 front diff only has a vacuum diaphragm that pulls the mechanical cable which lands in the differential which actuates a fork pulling the gear and making it active on the right CV axle output. I want to use the auto 4x4 push button option that I also pulled from the Silverado and mounted inside the van. I need to connect the two wire electric solenoid that shuts off or allows vacuum from engine intake to enter the front diff diaphragm vacuum line only when the transfer case calls for 4x4. I suspect the transfer case has to go into 4x4 first and then the front diff actuator but unsure if I connect to the transfer case control module or one of the two sources I see in a one-line diagram. From a one line wiring diagram for the push button panel switch controls I found there are two wires that activate the front encoder motor if it had one that was original on the silverado but the S10 has a two wire solenoid for the remote vacuum actuator. On the one line wiring diagram, one is called front axle switch signal circuit 1695 and the other is called front axle actuator control circuit 1296. Which one of these if either would I splice into, again I've been told the transfer case needs to go into 4x4 before the front diff I'm sure if this is true or not or how this is affected any help is very much appreciated. The picture is of one of the wiring diagrams and I highlighted the switch signal and actuator control.