It sounds like the RWAL valve you're referring. It may be leaking internally and you're seeing some evidence on the outside.

Can you post a pic?

The RWAL system is fairly simple. There are only 3 parts, the wheel speed sensor, the CAB, and the RWAL valve.

 

Not sure what the acronyms are, but I think you mean the valve body under the brake resevoira( It has a plug in connector ) and the sensor on the rear diff. What was the third? I don't have any electrical going to the front brake area, so I assume the ABS is rear only.

I can't really get a good photo of the valve body aft near the resovior. I can only see it seeping when I put my finger on it, but it does feel rusty.

 

that is your directional valve it allows fluid to go to front and rear brakes, but it sounds to me like the symptoms u give indicate rear wheel ABS sensor, they get full of metal dust, from rear diff fluid and mess things up, same exact thing happened to both my dakotas they do it around 125,000 , good indicator that rear diff fluid needs changed as well lol

 

i had a 1500 that once i hit 50 abs and brake light came on tryed the sensors 2-3 times it changed the reading a little pulled the pan and the rear end was going out and the ring and pinion was wabbiling a little and causeing the sensor to go crazy so i got rid of it for my dakota

 

EricBing, the rear ABS sensor you talking about getting metal is the same one on the Diff, right?
Moparman, Didn't the rear end make all sorts of noise before you found out it was bad? I had that happen on a Jeep, it raised all sorts of noise.
JOhn

 

RWAL - Rear Wheel Anti Lock
CAB - Controller Anti-Lock Brake, near the valve body.
Speed Sensor, just the one, in the differential.