I am having speedo issues with my 95 automatic 4x4 f-150. The needle is bouncing especially at higher speeds. I’m not having shifting problems like others have had on this forum (that I can tell), my abs light isn’t on and my overdrive light isn’t flashing. It’s just the speedo and cruise control which tries match the speed that the speedo is showing. I changed the vss in the diff as kinda a low hanging fruit with no improvement. I thing it was a bwg but I can’t say for certain. Next I pulled the differential cover and inspected the tone ring. All appears normal but I suspect that maybe it’s run out has become a bit off but it didn’t appear to be a gradual thing. Just came on. I was hammering it a few days prior when I got her stuck in the snow and throughly a broke a spider gear which in turn broke the tone ring. No such luck. I’d like some feedback. Change the ring anyway? Try a new speedo? Thoughts?

 

Most likely your problem is in the rear end
You transmission is not shifted off the VSS but it uses the OSS sensor on the transmission.
That is why you do not have a shift or overdrive light flashing.
I am guessing you have an 4R70W Transmission.

 

 

You can't have an AOD and an Overdrive light.

 

 

Just a quick update for anyone with this problem. Because I was dreading pulling the cluster (old plastic breaks easily) I went to ford and tried another VSS from the dealership this time. No luck. So I then pulled the cluster and brought it to a speedometer place. They confirmed that it was bad and was unrepairable. That bummed me out because I wanted to keep my mileage.

I went down to the junkyard and pulled the circuit board off the back of an f150 with the same engine and transmission (not sure if that matters or not). It was cheaper than buying the whole speedometer. I think three bucks vs 20. Anyhow plugged that in and fixed my problem. If you're going to do this make note of your mileage before you pull it because your new mileage will be whatever was on the source vehicle.

Also, you'll want to check what wheel size your speedo was programmed to before so you can match it up. Youtube PSOM programming. Looks pretty easy. In didn't change out all the bulbs but regret not having done so. 194 bulbs I think there's 15 or so. You can buy em in 10 packs so 2 would suffice. I also took the time to clean all the gauges and plastic really well. Oh, one other thing. My truck wouldn't start with that bezel removed because the tank switch goes there and it needs to be plugged in for the ignition switch to work.

 

You can also copy the information out of your old PSOM, working or not and burn it into your new PSOM and then you will have your old mileage + wheel set up.

 

95s seem to be a problematic year for the psom.
I had a similar problem w/ my 95. It had a bad solder joint.

How do you do this?

 

The speedometer place should have been able to copy PSOM to PSOM information for him.
Nigher PSOM has power applied to it while copying so it does not matter if the old PSOM is burned up or not as long as the EEPROM is OK.