i've got a 95 f150 4x4 and after replacing the rear drums & shoes, and an oil seal my ABS light came on and my speedometer doesn't work, it only jumps up to 10 mph at random.. after replacing the seal the differential fill plug wouldn't come out..eventually came down to drilling a small hole in it and using an easy out and small torch to remove it, i noticed a few nicks on the teeth of the "sprocket" on the left side of the diff gear(from my understanding it is part of the ABS?) i was told not to worry about it and continued..took it for a test drive and noticed the abs light and the motionless speedometer but everyone i've consulted tells me it has to be something with my transmission affecting the speedometer is this correct or would the damage to that "sprocket" be the cause? any info would help greatly as this is my only reliable vehicle

 

that 'sprocket' is called an excitor ring. it is very important in your transmission and speedo operation. try replacing the vss in the top of the diff before pulling the cover off again. they're super cheap and should be changed almost as often as oil on a truck that gets any offroad use. if that doesn't fix it, you better check that ring.

 

When you drilled the exciter ring you magnetized it. The ABS sensor on the diff is magnetic. if changing the sensor doesn't help you will have to remove the inspection cover and check for metal stuck to the ring.

Regards

Jean Marc Chartier

 

replaced on on my 1993 f150.. ABS light was on and speedo didnt work.. I payed 18.99 for the part at the ford place .. I unloosed one bolt on top of diff... slid the holding clamp away unpluged the old one and pluged the new one in , put it all back together and it was fixed .. real easy..

 

Actually, probably, when he used a torch on it is when he fubared it.

Darrin

 

i've been thinking and figured the heat could've damaged the vss but would the speedo still jump around if that was the case? also if i don't end up having to replace the ring, will the tooth on it that is damaged(i looked at the tooth and only half of it is damaged) cause the speedo to jump around at all or is it best left alone or replaced. btw i appreciate the help

 

Heat and magnetism don't mix.

Darrin

 

went out today & picked up a new sensor tried it with no success.. so i drained the diff & removed the cover to find a few unseen problems, the magnet from the fill plug had fallen off into the housing and the exciter ring had come loose. so tomorrow i'll be taking a trip the the junkyard in search of a good ring. anyone know the torque for the bolts that hold the gear & spool in? i think i read 77 ft-lbs

 

I use 80 FT Lbs. but here is the chart for the 1995 8.8".
http://i54.photobucket.com/albums/g9...199588Torq.jpg

That ring is the only thing that gives your speedometer its information by way of the PSOM and the VSS sensor on the rear end. It is used by the ABS module and the ABS module is wired in parallel with the wires going from the VSS sensor to the PSOM.
The PSOM also converts this information and sends it on to the PCM so the PCM can control the transmission if auto and adjust the fuel and timing.
The PSOM also sends information to the Speed Control for it operation.

The book say if you remove the ring always replace with a new one and never use a used one.

 

guess i lucked out that they wanted 300 for the whole diff and i couldn't just have the ring haha, but thanks a lot, what brand book do you have, mine simply says not to touch it, take it to a repair shop. how much do these rings usually run?

 

I only use Ford Shop Manuals.
And it says:
6. Remove the anti-lock speed sensor ring with a soft-faced hammer. Discard anti-lock speed sensor ring. Once removed, the anti-lock speed sensor ring cannot be reused. A new anti-lock speed sensor ring must be installed.

It looks like about $55.84, part # E7TZ-4B409-B from the place below.

http://www.drivetrainspecialists.com...duct-1116.html

/

 

alrighty i've got the ring coming tuesday.. $41 at the dealership. just have to get all the magnetic particles out of the housing & fluid..

 

got her back together after 3-4 hours of freezing my @$$ off. speedo & ABS are working good. big thanks to everyone