Have a 2000 Ford Ranger 4 banger, 5 speed. A couple of months ago the speedo needle started going for 70mph to 30 mph at hiway speeds. Local wrench replaced the ABS sensor on the rear axle and that worked for about a month. Problem came back exactly like before. Changed the sensor out again two days ago, and when I drove the truck today, it started it again.

Seems to need to be warm for this to happen. Anybody have any ideas what might be wrong?

Thankss

 

Welcome to FTE!!

I would start by pulling the RABS codes, since yours is a 4 banger you should only have RABS, I had an SOP for pulling the codes in the tech info thread when I was the moderator here.

 

I'll try that.

 

I think this is the SOP your talking about.
http://fords.kilonet.org/ken00/2000RABS.pdf

Just cause the mods have changed don't mean I am gonna pull that tech thread, it's still there and intact. I feel it's a good thing to keep right where it is. But would consider adding to it if you think of anything else. And would always welcome your advice Ken, as your one of the more respected people in here.

and twoidhd, welcome to FTE.

 

Since the weather has gotten cold, this problem as gone away. Anybody have any thoughts as to why this seems to be heat related?

 

No idea about being heat related, but I think I know what it is. In your rear differential, bolted into the top driver's side I believe is a sensor. It's a magnetic pickup that reads teeth on a ring inside the rear end. It uses this reading to calculate speed. They go out pretty often,and they are super easy to change. Buy one from Ford for about $15-$20, crawl under the truck, and unplug and remove the old one, pop in the new one and plug it up. No fluid will be spilled, and no major tools are needed(maybe an allen wrench or something). If you don't have a Haynes manual or something similar, invest in one, and it will show you how easy it is. This sensor is not realted to the ABS system, at least not directly, so those other sensors were probably not necessary.

 

Did that twice already. First one lasted about a week before it started acting up. Second one last two days before it went screwy. Like I said, since it's gotten cold, no more troubles. What's with that?

 

Don't know, but in your original post, you said he replaced the ABS sensor, which this is not, it's different. Sorry if I am confused, I don't know if we are talking about the same thing. Just trying to help, 'cause the '99 I used to have did the same thing, screwy readings, then just stopped working altogether.The new one fixed it though.

 

Is the ABS sensor close to the part you are talking about?

Thanks

 

Not sure, 'cause I don't have my manual handy. I'm currently sitting in a hotel room in the middle of nowhere Virginia, but I think they are seperate. The sensor I am talking about actually sticks inside the rear differential where the fluid is, and where your gears are located. It bolts on near the top, above the actual fluid level, and has an o-ring type seal to prevent lube from splashing out past it. When you take the old one out, you can look inside, or feel inside, and there is a ring with teeth on it that turn with your ring gear. The sensor is magnetic, and as the teeth pass by it essentially counts them, and determines how fast they are going. This signal is used by your computer to calculate engine speed. There is no cable from the transmission like the old days. I believe there is also an ABS sensor in that area, however, they are two totally seperate items. Again, a cheap Haynes manual will not only tell you what it is, it will show you it's exact location.

I may be on the wrong track, and I know the real mechanics in the forum could explain it better, and maybe they will chime in. My problem came and went at first, but it got progressively worse, and finally quit altogether. Come on guys, help a brother out here, we need info, pics, part numbers etc.

 

I have a 2000 w/ a V-6, the part he is refering to is a "vehicle speed sensor"
Mine just had the same prob, $22.95 at the dealer, and now all is right with the universe.

 

Thanks. I'll check it out.

 

Your thinking of the VSS sensor in the pumpkin of the diff.... Check the wires going from the sensor back to the front of the vehicle for rubthroughs. Check the fluid in the diff also. If it's low, it could be overheating??

 

Had same problem on 2000 4 cyl man. Changing the VSS didn't fix anything. Tracked the problem down to the large wireing connector that goes from under the truck to inside the cab, located right under the drivers seat. Road salt had corroded the terminals. After I fixed it all kinds of electrical problems went away.