I was advised month earlier on this forum to update my 87 truck 22RE with an Auto trans, with a speed sensor out of a newer truck, say early 90's which is located on the end of the transmission instead of the speedometer like the older trucks. Anyways I tried the newer speed sensor on my truck, and all attempts failed to get it to work. Has anyone else tried this?? And how does it wire in? The old truck has 2 wires, the new one has 3 wires. I am open to any advice. thanks

 

Where's the other thread?

What were ya tring to fix with the NEW speed sensor?
Is the OLD speed sensor (in the dash cluster) disconnected?

If ya take the cable out of the trans to install the new speed sensor, how the heck is the speedo supposed to work?

 

I'm not using the speedo any more, I just need the trans to shift. The only way the trans know to shift is if the speedo sensor talks to the trans sensor and say yep I;m moving, go head and shift. The newer trucks gets rid of a cable and speedo.

 

THe one issue I notices is that in my FSM the spec for hte speedo is one pulse per 40cm.

Assuming a stock 4.10 ratio and a 225/75R15 stock tire... I get ~5.56 pulses per rev.
The Marlin speedo claims 4 pulse per rev.
I assume the OEM one you snagged is 4 pules per rev?

Dunno if that is causing the problem.

I dont have a FSM for the newer truck to tell ya what the 3 wires are for versus 2 wires on the 89 (actually one wire off the cluster)

Is the speedo removed?

 

I don't understand why you were told to change to a newer model sensor. Are you using the 87 tranny , 87 ECU and 87 wiring harness? If, so I'd stick with the 87 SS too. Nice little buggys you're building BTW.

Edit, oh I see now it's a newer tranny isn't it? I'd look at the EWDs of both model years and see what the extra wire is for. You may need to use the newer ECU for the newer tranny.