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97-98 clusters are analog. The motor for the speedometer is inside the case, and can and will shred the white little gears. They can be replaced. Also the clear housing, holding the odometer system, breaks and won't hold the motor in position to hold constant contact with the gear mesh.
I have 5 clusters for these years, and 3 have broken clear mount housings. They seem to break over time and only get worse. I haven't tried to fix one with any glues yet, since I have others for use if needed.
Like White said, they draw the power from the 2 VSS sensors on that truck. The rear isn't usually the culprit, but the VSS on the transmission is in these models. Sounds like the system is engaged, just not fully functioning internally.. I'd personally check the cluster and go from there since you have already swapped the 2 electronic sensors. There isn't much more other than a damaged cluster in 97-98 models.
I I bought a used gauge cluster it does the same thing
Going about 70mph .and let off the gas it spkies the speedometer for a sec . It does this on the old cluster and the newer one
You should give more details about your truck. Has the speedometer ever worked since you've had it, or did you just buy this rig, non-working? You said that you bought a sensor then said that you need a sensor.
The short sentences are tedious.
There's not much to the system. There's a thing that spins the sensor parts causing the sensor to put out a signal. Sounds more like your problem is not the sensor but the mechanical spinning piece. Your sensor's not getting spun. Check the parts that spin the sensor.
Is is there a wrong way to put the VSS sensor on the transfer case in wrong.
It just slit in with a little twist
97-98 clusters are analog. The motor for the speedometer is inside the case, and can and will shred the white little gears. They can be replaced. Also the clear housing, holding the odometer system, breaks and won't hold the motor in position to hold constant contact with the gear mesh.
I have 5 clusters for these years, and 3 have broken clear mount housings. They seem to break over time and only get worse. I haven't tried to fix one with any glues yet, since I have others for use if needed.
Like White said, they draw the power from the 2 VSS sensors on that truck. The rear isn't usually the culprit, but the VSS on the transmission is in these models. Sounds like the system is engaged, just not fully functioning internally.. I'd personally check the cluster and go from there since you have already swapped the 2 electronic sensors. There isn't much more other than a damaged cluster in 97-98 models.
AK, will it still give the code for no VSS though? Does the PCM read out of the cluster, or straight off the gear? I never really thought about it, I guess.
I I bought a used gauge cluster it does the same thing
Going about 70mph .and let off the gas it spkies the speedometer for a sec . It does this on the old cluster and the newer one
That almost sounds like you've got a bad drive gear.... not the gear on the sensor, the gear that turns that gear.
Have you tried cruise control yet? Just trying to see if we can narrow this down at all.
AK knows more, for sure. But usually the speed sensor is two parts. An electronic part, and the mechanical part that fits inside the transmission. I checked out images on the old internet and it looks like the Ford VSS has the old mechanical speedometer cable tang sticking inside the transmission, to spin the electronic part of the sensor. Pretty common, the manufacturers kept the old mechanical parts, and just converted things to electronic. If the square tang isn't seated properly or if there's something wrong inside the tang doesn't spin. I put a picture below.
Sometimes it's difficult to get the square end in to the square hole. I've had other models of car where you could get it all clamped down but the square tang wasn't seated so nothing spun. One possibility. You should see it spin by eye if you get the truck up in the air, in gear, with the engine running and the electrical cable disconnected.
Full disclosure - I'm definitely just spit-balling here. I could be way off base.
Well... I'm thinking you should try the first sensor again. Maybe your speedo gear was stripped in the cluster, like AK said, and you bought a bad/wrong VSS.
One more thought: The VSS that you put in it.... was it brand new? If so, what is the part number? I am showing the VSS listed for E4OD and "Automatic Transmission", but nothing on the manual trans.
You have a spinny thing on one end and a spinny thing on the other end, and electrical wires in between. The spinny parts are easy to check. There's probably also a way to check the electrical signal on the wire. Not sure what Ford uses for their sensors, it has two pins so looks like a magnetic pickup type, maybe.
So, you can eyeball the spinny parts, and use a meter to check continuity on the two wires from the sensor to the gauge. You don't even need to know what type of sensor it is, the wires just need to be intact. Could easily be a broken wire.
Also... to add to my post about which sensor you put in it, I'd like to research the part number. Back in the Mustang's, the AOD and T5 used the same sensor, different gear. So it may very well be the same VSS between the 4R70W and M5OD.
