Got a 95 1/2 ton with 180,000 miles, automatic 5.8 liter. I been having trouble very recently with hard shifts and ABS and CEL comimg on. I had no speedometer problems. The hard shifts were off and on. I replaced the MLPS last week and that did not solve the problem. I replaced the VSS today and the shift problem is gone, it shifts like silk. But! Now my speedometer goes crazy only on the highway. I don't have much time, I'm going on a trip Tuesday early and can't do without the speedo or cruise control. I would rather put the old one back and put up with the shifts. I am gonna try to check codes tommorrow. Could there have been a problem with the install of the new VSS or could it be bad? I have read up a bunch here on the forums and I realize there are other things it could be such as the ABS module or PSOM. I just don't have much time left and need my speedo but would like to have a normal shift on the trip also. I also tryed pulling the fuses for the ABS but no help. If it is an ABS problem is there a way to disable or unplug it since I think its only rear ABS? Or will that do more harm. I have not had OD problems and the OD light has never came on or flashed. I'm in a bind for time and sure appreciate some fast help. Thank you.

 

cold be the actual speedo gauge itself

 

I pulled codes with my little scanner and only got a code 33 having to do with the EGR valve. I traced down all the wiring from the VSS on the rear end and could find no bad places in the wiring. I reinstalled the old VSS and the speedo works normal. It also shifts normal but it was off and on before anyway. Also the parts store said there was another VSS on the transmission?? Hmmm, not sure what to do now.

 

NO!!! The older models had it on the transmission but not in 95.. sounds like maybe you got a bad sensor... Make sure the plug is nice and tight on the VSS, it wouldn't hurt to put some dielectric grease in there...