No 4 Low, think it's the speed sensor

jco77on · Mar 30, 2015

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 · Mar 30, 2015

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 · Mar 30, 2015

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 · Mar 30, 2015

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 · Mar 30, 2015

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 · Mar 30, 2015

shortzt said:
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 · Mar 30, 2015

shortzt said:
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 · Mar 30, 2015

I'll find out tomorrow, its worth trying

shortzt · Mar 31, 2015

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

shortzt · Mar 31, 2015

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

No 4 Low, think it's the speed sensor

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