Speed sensor codes

Ok here's the lastest in the on going saga of what I thought was a wednesday built truck cause nothing was ever going wrong with it...

It started shifting really hard, rev up and slam into 2nd, then it would run the gears up to high in 15 or so feet. I had the tranny rebuilt a while back so went back to him and pulled the speed sensor code. Changed it out and no issues.

I had the O/D turning it's self off for a while with the bouncing speedo needle and thought..."Speed sensor is going again" Changed it out about 2 weeks back to a brand new fresh out of the box sensor and no O/D issues, speedo still twitching a bit but running good.

Now back at it again. Last night same thing, shifted hard O/D lamp flashing running the gears, head back to the tranny man and pulled another speed sensor code. Checke everything out cleared the codes and ran it home. Shifted like butter and ran great. This morning went to leave a light and reved up to like 12k and started moving then banged 2nd again.

Headed back to the tranny man and guess what...another speed sensor code. So all the wiring, speed sensors, ABS module and anything else he could think to check seems to be working. He says maybe the twitching speedo head may giving the computer fits, maybe the computer maybe I have no clue.
I hate to start tossing ABS modules, speedo heads or computers at it just to see if it works, has anyone experienced this or anything like it? Any ideas or suggestions on what else I should be looking at? Tranny's fine just in case...and of course it ran just perfectly for him

Any and all help is most appreciated...

Ron

Could be a wierd wiring problem, which would be hard to nail down. I'd first change the gear oil and check for metal contamination. Metal particles can cause sensor issues.

It's all been done. Changed out the rear lube and cleaned the houseing. When I switched out the rear sensor the last time I looked for metal but everything was clean. All the wires were traced and none are chafed, chewed or rotten. We're beginning to think its the PSOM. When I went into the manual I can't find any information on it so I guess I'm not looking it up right. But at the moment that's where we're heading. How does the computer store milage? If I change the PSOM out will I start over on the odometer?

i believe the mileage is stored on the speedo itself.looking at the wires tells you nothing other than its not chaffed or visually broken.you need to "feel" the wires to see if it is broken inside the insulation or do a continuity(SP?) test on the wires to see if they are broken.i believe the only thing the PSOM does is calibrate the speedo for your gears and tire size.but i have been wrong before so dont hold me to it.

Is there a way to test the RABS sensor?

ok guess i was wrong about the PSOM

http://www.dashusa.com/ford_trucks.htm

94f450sd said:

ok guess i was wrong about the PSOM

http://www.dashusa.com/ford_trucks.htm

Click to expand...

Good link Rich, that sounds an awful lot like what Rookie has going on here.

its amazeing what google searchs come up with

Interesting. Would be worth calling those guys and see if they think a bad PSOM could set a speed sensor code.

Rich, I don't care what the others say you are the man .

That is exactly what I spent the morning looking for. I just got back from the store and it drove perfectly until the last mile and it all started over again. I'm dialing those guys as I type. I'll let everyone know if this is the fix. It sure sounds like it.

I have to figure out what I'm doing wrong l when I go to search mode...

Thanks
Ron