Pawpaw, ? for you, the other day he took it out and cleaned it and reinstalled and it worked for 40 miles. is it possible that he has metal shavings and/or low fluid and that is effecting the magnet in the sensor and when he cleans it off it works until some crap gets in the way?

 

I suppose it could be shavings on the sensor, but i've never heard of this failure mode.

So lets review what he has posted, he said the speed-o with the new speed sensor immediately acted just like the old one, work for the first 5-10 minutes, then drop from 70-0.

He said he recently removed the new speed sensor & reinstalled it (no mention of metal on it) & the speed-o worked for 40 miles & failed again.

So he could try messing with the speed sensors wiring or electrical connector & see if it'll work again & if it does, then the problem is likely external with the wiring, connector, pins, or sockets.

If that doesn't produce results, pull the speed sensor & look for debris.

If no debris, then suspect it's the new speed sensor, not likely maybe, but possible if Murpheys Law is messing with him!!!! lol

A scantool that'll read PID's, hooked up to the in cabin diagnostic port & set up to monitor the speed sensors PID to the computer, would show if it's corrupt, or missing.

 

Haven't had a chance to check the wiring - been working alot. But, I hate to be a problem, but if the cruise works off the VSS, if it's got a frayed or broken wire, wouldn't the cruise stop working also?

 

It seems like these sensors are some kinda voodoo. In what I have seen people report it can effect any of the systems mentioned in many different ways. You would think that "sensor fails" then "xyz areas that run off said sensor" should fail. But it does not seem to be that way. The truck/sensor seems to pick and choose what it wants to do with the bad signal.

 

I would like to reiterate. I would replace the vss/abs with a motorcraft if you can get one.

 

I am by no means a mechanic. However I try to fix things myself when possible. I believe this forum saved me a lot of money. My truck started shifting hard, dead speedo, cruise didn't work, and ABS light came on. After reading this forum I went to Auto Zone and got a sensor. Didn't work, so I got the factory sensor, no luck. Finally as a last resort checked the wiring, as was also recommended by someone on this forum. About two feet from the sensor, the wiring had been worn through (pinched at frame). I used a butt connector and problem solved. Thanks to all that posted info; my wife now thinks I'm brilliant (lol).

 

Welcome to FTE damka.

Good trouble shooting, feedback & to hear you found & fixed your corrupt speed sensors PID to the computer.

So by visiting FTE, finding & fixing the problem yourself & impressing the wife, you've managed to double your pleasure!!!! lol

Hard to beat that, to start the week off!!!!

 

Welcome aboard! Glad you found a solution to your issue and were able to fix it. This board, and more importantly the people on it have helped me and saved me more money than I can count. Stick around and I am sure there is more we can help you with!

 

I hear people say vss is in rear xle i watched a tranny teardown video and inside trany on sipport tgere is a sensor my tranny is taking off in high gear would that sensor cause the problem i rebuilt tranny clutches pump converter still have problem anyone experience this problem please help

 

Welcome to FTE.

Don't begin throwing parts at your problem on a whelm.
Scan the tranny computer with the inexpensive ELM scan tool, while running FORScan on the viewing device of your choice, as discussed here. https://www.ford-trucks.com/forums/1...-scantool.html, then post up All trouble code Numbers, as they can help focus a trouble shoot.

I'd begin a new thread, so you get answers just for your problem. Go atop this forum thread index page & click on the "New Tread" tab, located atop the left side of the column thread stack.
Enter more vehicle info than the 1998 year & mileage range listed in your signature, enter things like engine, tranny, cab style, repairs, did the problem come about suddenly after some event, ect.

The 98 had the ABS speed sensor located in the top front center of the rear differential pumpkin. This sensor & it's wiring have been the source of most of that systems problems. The sensor has been most likely to give problems. As has been mentioned in previous threads, a number of systems depend on this sensor providing uncorrupted output, for them to do their thing & yes the tranny uses this PID.

If a trouble code, or scan tool live PID feed shows a feed interrupt, suspect the sensor, or it's electrical connector, or a wiring run problem as mentioned in earlier posts.
For reference, the electrical resistance/continuity on my new rear ABS speed sensor was 1.9K ohms.
Some beginning thoughts for consideration, let us know what you find.