'95 KW W900 with a cat 3406e Speedo/tach/cruise problems

For starters all of the research I've done says replace the speed sensor but I did that & it didnt help, now to my problem......I have a '95 KW W900 with a cat 3406e & Eaton 13 speed, so my tach reads about 1000 rpm lower then where it should, my speedo will fluctuate some (just a couple mph, not completly drop to 0 & come back up) & when I step on the accelerator to speed up the speedometer needle actually falls instead of climbs. This is causing my cruise to mess up because if I have it set at say 60 mph & hit a small hill so the truck has to accelerate, the speedo actually drops like I said so the truck thinks its slowing down even more & will take off on me. It will shoot to 75 or better if I let it. So far i have check & changed out the speed sensor, checked the yoke off of the output shaft & looked over whatever wires i can get my hands on between the sensor & ECM. Is there anything else that could cause this?

 

The sensor I replaced was on the back of the tranny off of the output shaft

 

Didnt know there was a second sensor on here, thought there was only one. I'll look into it, thanks

 

Haven't had it in yet to get scanned but I'm wondering the same thing. Would the timing sensor on the engine explain the speed & cruise problems though?