problems with speedo

[Claire Carter]

I live in the UK and have a 97 ford explorer right hand drive. About three months ago my speedometer started behaving eratically, the needle flicking about and going down to zero all the time, when this is happening my rev counter is also a bit lower than normal and the car doesn't seem to go into top gear. This problem stopped as quickley as it started, so my garage said if it does it again bring it in. Well it did it again yesterday, the garage replaced the speedo sensor - this didn't work. They also checked the drive shaft and all seemed to be ok. I had a recall done on my explorer re. throttle assembly about 7 days prior to this problem occuring but the garage say it's nothing to do with it. The garage seem to be at a loss, apparently nothing shows up on the diagnostic computer.

 

[fordkrazy]

well as far as i know all explorers have mechanical spedo's unless you have a digital instrument panel. (that would be sweet) any way some times the gear assembly in the tail housing of the transmission comes loose and the spedo gear skips, or the plastic fitting on the end of the cable that engages in the gear gets stripped for one reason or another. the actual guage could be faulty but i highly doubt it. what i would do is ( you could do this yourself) is look at the end of the transmission and look for a hose looking thing going into the side of the transmission. it will screw into the transmission like a garden hose. check to see if its tight. if its not tighten it and that was probably your problem if it is tight then (this depends on how mechanicly inclined you are cause some things may pop out and you may have to figure out how it goes in or buy a service manual)unscrew it and pull it out and check the gear and the fitting on the end of the spedo cable. if either have rough marks on them or the gear has missing teeth then you will need to have one or both replaced. hope this helps.

 

[Robert]

No, his '97 has an electronic speedometer (still an analog gauge though). His has a Vehicle Speed Sensor (VSS) mounted in the transmission or transfer case if it is a 4WD. It resembles a very small plastic pinion gear and has two wires that come out of it. The two wires go through a harness eventually to the Processor Control Module (PCM). It deciphers the vehicle speed and then sends the appropriate signal to the speedometer in the dash. More recent models ('99 for sure, possibly '98) use the Rear Anti-Lock Brake Sensor which is mounted in the rear differential as the VSS.

If the VSS was just replaced, then I would check out the wires at the VSS and at the back of the speedometer. It also wouldn't hurt to take a second look at the VSS.