I have a '99 7.4L K2500 Burb with an auto-trac np246 that has failed.
I picked up a np241 that I'm going to use in it's place. I'm looking for info on wiring the 241 vss to the 246 vss harness.
It looks like the 246 has two sensors at the rear and one for the auto-trac.
Does anyone have first hand knowledge on what wires from the 256 I need to splice to the two wires coming from the 241.
Thanks for any help.

Aaron

When i did mine i used the rear most VSS. The 241 has three wires coming off the shift lever. one of the outside wires needs to be grounded. The other outside wire needs to be ran to the front diff for an actuator signal. The middle left alone or run to the floor shift lever. Its been a while since i did this. Ill crawl under my Tahoe if you need more specific info. The large harness going to the 246 pretty much gets cut off.

Thanks for the info . I found an old post that had the info. The green and purple wires hook up to the 241 vss. I test drove it and it worked fine.
The 241 came out of a early 90's GM and has a 2 wire indicator instead of the 3.
I still have to get the driveshaft. It has a companion flange instead of a end yoke of the front output. I'll need to find a driveshaft that is a direct replacement or a flanged yoke and build my own.

I have a 1999 taho with the np246. Cant find a cheap one. What can I convert to that is cost effective?

The 246's aren't as bad to fix financially as they used to. If you really want to get away from the 246, then the only simple option is the mechanically shifted 241. You will need a front driveshaft from a 95 and newer to clear the neutral safety switch. You will also need a shifter and linkage. Make sure to get one with the same input spline count. There are different input gears for the 4l60E and the 4L80/Manual.

A 261 would be an option, but you would still have the same crappy magnesium case. The front driveshaft would be reusable with this swap.

If you ever need parts to fix t-cases, be it new or used, let me know.

241 = linkage shifted
243 = electrically shifted
246 = viscous coupling electrically shifted

Got around to getting a front drive shaft(good thing I have other 4x4's) thought I would bring back this old thread to keep all the info in one spot.
I'm trying to figure how to engage my front diff, so I cab use 4 wheel drive.
I would like to use the buttons in the truck. Anyone change out their NP243 or NP246 for a NP241 and figure out the fornt axle actuator?
Thanks for any help
Aaron.

Stock Chevy IFS 4WD acctuators are junk and prone to failure. Go manual.
http://www.4x4posi-lok.com/app_chevy-k.html

guidolyons thanks for the info. I may do this if mine quits working but in the meantime I need to get this hooked up. It's been unused for the last year so it may have crapped out.
I'm going to try and chase the wires out and figure it out tomorrow. I'll post up what I find out and how I(f) I fixed it.

Bringing this one back from the past to ask some questions and correct some confusion the best I can. I have an '01 ECSB z71 4L60E. I used a np241 out of a '91 light duty k2500 and the driveshaft from it as well. So for all of you who have the driveshaft out of a pre '95, it WILL work. It was a 700r4 truck so the installation was straight forward and easy. Everything went in perfect except the front driveshaft was about 3/4in too long. So I took the driveshaft apart (It slides apart) and used a chop saw to cut 3/4in off of the splines. Then I cleaned up the splines the best i could with a metal file and then greased it (be careful to not put too much grease on it or it won't compress all the way and will seem to still be too long.) I got it in the truck and got the u joint straps tight and everything. The VSS was pretty straight forward as well. Just cut the 241's vss and wire it in to where the 246's goes, matching up the wires colors. Now, what DOESN'T work. This is where I have my questions. I've read every post on google I could find about 246 to 241 swaps and multiple times they have said that you ground one of the outside wires on the 241's wiring harness and send the other to the black/grey wire on the front actuator. So, I assume that the way this works is that the 241 has just a basic switch in it that completes the circuit and grounds the wire that goes to the front diff. So i just grounded the black/grey wire on the front diff with a switch (so i could have 2lo when i wanted) but it didn't work. So I went to my work (autozone lol) and looked up as many wiring schematics as I could find. According to them, the black/grey wire is the signal wire that goes back to the TCCM to tell it that it has fully engaged, not what tells it to engage/disengage. After playing around with my multimeter on the front actuator, it seems that adding hot to the light blue wire makes it engage and taking it away makes it disengage. But however, when I try to wire 12v hot from the battery to it, it doesn't work. Somebody please help me on this? So as of right now to put it in 4wd, I have to put the tcase in 4x4 then put the fuse back in for the TCCM and it locks the front in. So I need help from someone who has got it to work and took it out and made sure the 4x4 was actually working. And also, does anyone know which wire goes from the TCCM to the ECM that tells the ECM when the tcase has failed and to trip the service 4WD light?