Hey, I'm the new guy on this site, and a new to Ford f-150 owner. I have owned Chevys for years and made the switch.
Now on to the problem. It is one I have seen on this site, with not clear cut answer.
Bouncing speedometer, No cruise control, abs activates every time I stop. No warning lights on dash activated.
Changed the speed sensor, Recently had the ring and pinion changed. The guy who did it said a couple of teeth on the tone ring were bent and he straighted it out.
Any Help ?? I hear and read change the tone ring, change the speedometer, change the psom ???? Is this part of the speedometer
Thanks,
Boilerperson

 

Welcome. Someone will be along that can answer this one. I just wanted to bring this to the front so that maybe someone that knows the answer will see it.

 

The PSOM is the "programmable speedometer/odometer module", so in reality the speedometer is technically part of the PSOM. I would be leary if the guy said he found some bent teeth on the tone ring but he fixed them. How would they have gotten bent in the first place if he didn't do it while he was in there?

 

The bearings went bad in the the rear (real bad). I knew it when I bought the truck, but I got it at a good price. Because of the bearings being very bad and giving the ring and pinion all kinds of play, it knocked two teeth off the ring gear. I'm sure when this happened it bent the tone ring teeth.
Is the PSOM a seperate piece ? If I remove the speedometer is it attached?
Also Is there a way to test befor I tear apart?
I thougt if there is some kind of signal simulator that I could plug in at the rear speed sensor to simulat a certain MPH, if the speedometer is OK with a good signal, it's the tone ring. If it still bounces, It's the PSOM.
??????

 

You'd need a function generator to simulate the ABS sensor signal, but if you have GoldWave (software), you can use your stereo to do it. The second pic is me doing that. Read this thread.

 

Steve 83, thanks for the information. However I am not familier with Gold Wave software so I am still not able to figure out how to simulate a signal.
Now for an update....
I unplugged the connector from the rear sensor.
The pulsating brake went away, the ABS light went on. Of course the speedometer did not work.
One guy at the local Ford garage insists it will be the tone ring. If I do give this a try will the dealership know which one I need ?
A guy at a different Ford dealership insisted my speedometer read from the transmission. It does not.
A person at a local garage (the one that did my ring and pinion) said he does not think it's the tone ring be when he removed my tone ring from the ring gear there were tow bent teeth that he straightened out.
He said try hooking up an AC volt meter to the speed sensor and see if I get a steady signal.
does it really have to be this difficult to repair my speedometer, cruise control, and ABS ???

Thanks, Boilerperson

 

GoldWave (shareware)
LAME (freeware)
WinAmp (shareware)
GoldWave has a built-in function-generator that you can use to make a square wave of a specific frequency, then use LAME to encode it into an MP3 and play it on WinAmp to a decent amplifier that will send the signal to the sensor input of the PSOM, and use the volume control to slowly bring the amplitude of the signal up to the point that the PSOM detects it. I think I was using ~1300 Hz in that pic.

I think it IS the tone ring. When the guy bent the teeth back, he couldn't have gotten them perfectly aligned, and they were probably mashed flat, anyway. That means they aren't producing the same signal as the other 106 teeth, so every time the ring goes around, the ABS & speedo think the tires are coming to a dead stop for a millisecond.

There's only one tone ring for the 8.8" axle, and it has 108 teeth. It can be changed without removing the ring gear from the carrier, but the diff carrier has to come out of the axle.

 

Steve,
I also was leaning to the tone ring. You convinced me.
I talked to the guy who did the rear and he is willing to install a new tone ring at a very good price. I'm going for it !!!!!
Thanks again, Boilerperson