No 4 Low, think it's the speed sensor

[jco77on]

Like the title says, I have no 4 Low. 4 HI works great, but when I shift to neutral and press the brake and hit 4 Low all I get is a flashing 4 Low light. I think I've tracked it down to the speed sensor on the transfer case (output shaft speed sensor, not vss). After a lot of searching I found a part number: E6TZ7F293A. Problem is this stupid little sensor runs from $75-130 depending on where you look. Anybody have a parts 1350 they could pull this off and sell for less than the insane cost of a new one is?

 

[shortzt]

If you want cheap you can pull the module in the dash and find the wire that is the nss which senses that the vehicle is in neutral to switch to 4 lo and just ground it, just make sure you're in neutral when you do shift into 4 lo I did this on my 87

 

[jco77on]

No, it's not the neutral sensor that's on the transmission. I know that's good. This is the speed sensor on the transfer case.

 

[shortzt]

If I'm understanding you right mine did the same thing, the speed sensor controls the electric "motor" that spins up the clutches to give you shift on the fly, if I remember right its a brown wire that goes to the tcase, 4 lo won't shift on the fly it uses the speed sensor and a nss, not the one on the transmission, its one that's goes to the 4x4 module, if you want to try and test it to see there is a wire going onto the module that you can ground, its worth the try before you spend $70,

 

[shortzt]

I'll try to figure out what wire to ground to see if that will work, I cut my wiring harness out or I would just go and look

 

[jco77on]

If I'm understanding you right mine did the same thing, the speed sensor controls the electric "motor" that spins up the clutches to give you shift on the fly, if I remember right its a brown wire that goes to the tcase, 4 lo won't shift on the fly it uses the speed sensor and a nss, not the one on the transmission, its one that's goes to the 4x4 module, if you want to try and test it to see there is a wire going onto the module that you can ground, its worth the try before you spend $70,

No, this is the sensor that has a light blue and light green wire going to it. I believe you are correct about the brown wire, however, 4 lo, you can't shift on the fly (on the 89's anyway, can't speak for other years). Have to be in neutral, stopped, with your foot on the brake.

 

[jco77on]

I'll try to figure out what wire to ground to see if that will work, I cut my wiring harness out or I would just go and look

Thanks, I appreciate the input!

 

[shortzt]

I'll find out tomorrow, its worth trying

 

[shortzt]

It should be the red/white wire on the 8 pin connector going to the module

 

[shortzt]

Unless its a manual trans then its a light blue/white