I have a 1996 F-150 with a 5.8. often times the speedometer won't read or flood around, turning on the overdrive off light and also making me get stuck in one gear until it revs up and slams into gear. Sometimes more than once. I'm pretty sure that's rough on things as well as annoying and probably going to get me a ticket someday. Anyone ever had this issue and if so how did you fix it? And I've already replaced the rear axle speed sensor more than once and the gauge cluster. Many thanks.

 

I could be wrong, but i thought the 96 F150 still had the VSS/vehicle speed sensor on the drivers side of the transmision

I believe the sensor on the rear diff is only for the ABS. In other words it does'nt do anything important.

 

Probably up top where I can't see it

 

All speed information comes from the rear axle sensor in a 1996 truck. If you already tried replacing the sensor and the speedometer module (PSOM), the issue is either:

Fault in the ABS system
Fault in the cruise control system
Fault with the speed sensor wiring

To isolate the cruise control system, you can simply unplug the cruise amplifier/servo under the hood.

 

Could be the cruise. Ford had a recall a year ago but we couldnt get in in time. It quit working a year or two ago but wouldn't work when the shift problem arose before that. We guessed wiring but weren't sure where to start with that one.

 

ABS light is always on. I have a code reader probably should use it

 

The cruise, ABS and speedometer issues are likely related, since they all get their speed information from that sensor on your rear axle.

 

You might be onto something there. I think I remember reading about how in the rear differential if there's a little gear chipped/bent etc., It will cause this issue.

 

You cannot read the ABS codes with a Code reader.

Here is a procedure and Flashout Code definitions: RABS Codes

 

On my 96 Explorer the VSS plugs into the drivers side of the transmission tail shaft & the sensor on the diff is only for the ABS. I thought this F 150 would be the same, i guess not

 

Thanks. I'll have to find some things to make a lead wire out of in our shop. I found the wire to test though. Also can't do a whole lot with the truck at the moment. My 15 minute thermostat change turned into how do I get a broken headed bolt out of the engine block.

 

Your 96 Explorer has a 4R70W trans with an ouput shaft speed sensor unlike the OP's F150 with an E4OD transmission. That's why the rear axle VSS is used for the antilock brake system and speed/odometer, speed control, and PCM input.

If the OP's truck had a 5L engine and the same 4R70W transmission you would be correct. But that signal goes only to the PCM, it does not go through the PSOM.

 

Well now i know, thanks

 

Do 96s have brake switch leak?

 

Yep, and so so the 97 250's & 350"s