the one that goes on the diff. $30.99 at oreily auto parts. the old one broke in the diff. took me bout 2hrs to get it out. when i got the new one in, the engine light went out, but the abs and brake lights are still on and the speedo still isnt working. went back to the condo, disconnected the neg. battery cable and let it set about an hour. when i reconnected the cable and test drove the truck, the lights are still on, and the speedo isnt working. im hoping its the cpu hasnt caught up yet.

 

yeah if the abs sensor goes out you lose the speedo odometer and od lock-up. other words you will get sh##y gas mileage!
and it is easy to spot and replace.
i found it and changed it with 20 mins. it only 3 bolts holding it on. and its the only sensor on top of the rear diff.

 

i also changed the park neutral switch on the trans a couple weeks ago. and now the reverse lights come on anytime the engine is running. whether the trans is in park or any other gear. im asuming the switch is the problem. any ideas?