Help with LS Swap dealing with 4x4 and NP241 TCase. Speed sensor.

[NastyBuzzard]

I am LS Swapping a 1987 GMC V1500. It is kind of a unique swap, especially when concerning wiring.

My build thread is here. http://67-72chevytrucks.com/vboard/s...627161&page=17

I am using a 2001 4.8/4L60E NP241 (PS drop out of a 91 K5) setup. I am using the instrument cluster and column out of the 2001 donor and wiring the truck with the 2001 wiring harness.

I need to hook up the speed sensor so I can drive in more than just 1st gear.

Any help on how to do this?

Also there seems to be a harness for the transfer case that ties into the rest of the transmission harness but I cannot find where to plug it all back in! I searched and searched and found nothing. Any insight on this?

Also anyone know what size bolts it takes to attach the front drive shaft to the NP241?

[Clyde65]

I believe if it is only in first gear, then your in limp mode and it is actually in a higher gear but wont move very well.

With all the 2001 stuff your using, the speed sensor\wiring should be all intact and plug and play. is the harness chopped up?

[NastyBuzzard]

Originally Posted by Clyde65

I believe if it is only in first gear, then your in limp mode and it is actually in a higher gear but wont move very well.

With all the 2001 stuff your using, the speed sensor\wiring should be all intact and plug and play. is the harness chopped up?

It isn't in limp mode, I just don't have the speedo hooked up. It is in 1st gear and moves fine just won't shift because no speedo hooked up.

The harness isn't chopped up.

The harness isn't plug and play because I am not using the 2001 transfer case because it is drivers side drop, it also has a different speedo sensor that I don't think will bolt into my 241? I could be wrong though.

Kind of the problem is that the 2001 Silverado harness feeds down to transmission and transfer case, however the harness for the transfer case can unplug somewhere from the wiring harness. I unplugged it and set it aside last year so it wasn't dragging the ground, now I don't remember where it hooks back up.

[NastyBuzzard]

Any help on this? What I am doing is basically like if I was Solid Axle Swapping a 2001 Silverado with a GM Dana 44 and NP241 passenger side drop.

I worked on it forever last night.

The 2001 transfer case harness is on the left and the plug for the 241 VSS is on the right.



The harness has 2 male plugs that plug up under the hood near fuse box. I found one female plug for the harness right near fuse box but couldn't find the other to plug in. I grounded it and tapped the 91 vss wiring onto the 01 harness and couldn't get the speedometer to work at all.

I still need help on this. If I can do this I can take it for a trip to see how it does.

[clinebarger]

IIRC, A 2001 4x4 has a VSS Jumper Harness, Probably in the harness in the pic But I cant see it. The Jumper harness just extends the VSS wires for 4x4 models.

Locate the Jumper Harness, Cut the Male connector off, Locate the Original '87 VSS connector, Cut it off the harness (Leave enough wire to splice) Splice the '87 VSS connector onto the '01 Jumper Harness....Polarity doesn't matter.

Locate the VSS connector at the Main engine harness under the truck, Wire colors Purple/White & Light Green/Black. Plug the Female end of the Jumper into VSS connector, Plug the other end into the '87 VSS on the T-case.

Here is a drawing that may help.....

[NastyBuzzard]

Thanks! That is what I was assuming! There must be an extension harness! I cannot find one for the life of me though.

I did take better pics I will upload when I get to my laptop.

However, I took the pigtail from the trans harness and just wired the 91 vss to it completely bypassing the other harness and it seems to work. It will probably cause issues when I try to use 4x4 though. Idk.