4L60E w/ 91 NP241 Speed Sensor Help
08-26-2015, 06:28 AM
#1
4L60E w/ 91 NP241 Speed Sensor Help I have a 87 GMC 4x4 that I have installed a 2001 4.8/4L60E with a 91 NP241 Tcase out of a K5.
I am also using the instrument cluster, steering column, fuel pump and about 90% of the 2001 donor wiring harness in my swap.
My build thread can be found here: http://67-72chevytrucks.com/vboard/s...1&goto=newpost
So the problem I am having is I can't get my speedometer to work, so I am stuck in only first gear. I am dying to get this thing out the shop and take it for a test drive!
So far I have figured out that the transfer case wiring is separate from the transmission. It plugs in near the fuse box under the hood then runs down the frame to the transfer case. There are two male ends, I have one plugged in but the other I can't find the female end to.
It has 3 plugs on it, 2 of which seem to be exactly the same with the exact same wiring (2 wires) and one plug that has 3 wires.
I have the pigtail from the speed sensor from the 91 (2 wires) and I have tried to splice in the wires to the 01 harness but I cannot get it to make the speedometer work.
Can anyone provide any insight or wiring diagrams or something to help me?
Basically what I am doing is like putting the NP241 passenger side drop in a 2001 Silverado 4x4, like if I was SAS it. I tried to research that but I am coming up empty handed.
Please hold my hand on this so I can take her for a spin this weekend.
I am also using the instrument cluster, steering column, fuel pump and about 90% of the 2001 donor wiring harness in my swap.
My build thread can be found here: http://67-72chevytrucks.com/vboard/s...1&goto=newpost
So the problem I am having is I can't get my speedometer to work, so I am stuck in only first gear. I am dying to get this thing out the shop and take it for a test drive!
So far I have figured out that the transfer case wiring is separate from the transmission. It plugs in near the fuse box under the hood then runs down the frame to the transfer case. There are two male ends, I have one plugged in but the other I can't find the female end to.
It has 3 plugs on it, 2 of which seem to be exactly the same with the exact same wiring (2 wires) and one plug that has 3 wires.
I have the pigtail from the speed sensor from the 91 (2 wires) and I have tried to splice in the wires to the 01 harness but I cannot get it to make the speedometer work.
Can anyone provide any insight or wiring diagrams or something to help me?
Basically what I am doing is like putting the NP241 passenger side drop in a 2001 Silverado 4x4, like if I was SAS it. I tried to research that but I am coming up empty handed.
Please hold my hand on this so I can take her for a spin this weekend.
08-26-2015, 07:49 PM
#3
I thought the 90-91 used a 40 tooth output the same as what the 01 would have, making it an easy "wire it like the 01 with signal from the 91 T-case" job. 91 used a DRAC though, IIRC, and 01 would have signal going straight to the PCM.
Start with making sure there's voltage from PCM to VSS. Then troubleshoot it with factory manual troubleshooting like pretty much any similar year truck.
Start with making sure there's voltage from PCM to VSS. Then troubleshoot it with factory manual troubleshooting like pretty much any similar year truck.
08-27-2015, 05:24 AM
#4
What I found out is that there is a separate harness for the tcase wiring. It runs down the frame rail separate from the transmission harness. Then there is a pigtail on the back of the trans harness that would work for 2wd, but what they did is had a jumper harness to connect that pigtail to the separate transfer case harness.
I am missing that jumper.
What I did yesterday was just tie in the 91 plug into that pigtail on the back of transmission harness and voila. It worked, not sure how this will affect the other aspects of not having that separate harness. I know I will need to make a switch for 4x4 indication.
01 harness on left. 91 pigtail on right.
This is the end that goes up where the firewall is.
Here is the rear sensor plugged up and the 4x4 indication plugged up but then as you can see the other plug goes no where and the vss plug doesn't even go back through the transfer case harness.
I am missing that jumper.
What I did yesterday was just tie in the 91 plug into that pigtail on the back of transmission harness and voila. It worked, not sure how this will affect the other aspects of not having that separate harness. I know I will need to make a switch for 4x4 indication.
01 harness on left. 91 pigtail on right.
This is the end that goes up where the firewall is.
Here is the rear sensor plugged up and the 4x4 indication plugged up but then as you can see the other plug goes no where and the vss plug doesn't even go back through the transfer case harness.
