MODERATOR's NOTE: The images that went along with this DIY have since been removed by the author. However, it is still good for information purposes.

Okay, while looking for a new Solenoid, I noticed quite a few were refurbished. I was wondering what does one do to refurb a solenoid, so I decided to try it for myself.
What follows is the process with pics, sorry if they are not too good, I did them with an iPhone.(note to be truly refurbished the copper wire would be replaced, but I think you would only do that if the solenoid didn't react to having power applied) Cleaning all the ferrous metal shavings off the wire and the other parts should help allot.

So you will need:::

Channel Lock plyers
A small "tech" flat-blade screwdriver
a #1 flatblade screw driver
a vise
a c-clamp
a can of Electric contact cleaner
A magnet (optional)
a 12VDC power supply (battery or whatever, just has to be 12vdc)

First off, I'm going to start with the sensors out, there are a few DIYs on the transmission already. Basically you just drop your pan, remove four bolts and two screws and the governor assembly comes right out. The solenoid pops out and the sensor is held in by a clip.

Mine was full of metal shavings...





Start by putting the solenoid in a vise, don't tighten it to tight, and be very carefull not to break anything.

After it is in the vise, carefully pry the four tabs holding it together back with a small flat blade screwdriver....



You will then slowly remove the top portion with the filter. Be very very careful, there is a micro-sized check ball that may be stuck to this portion, though it should stay stuck to the magnet.


like so....

Then take the ball and stick it to a magnet or put it in a bag for later, I put both the ball and the spring in the solenoid on a shop magnet.



Then remove the solenoid. Clean it with contact cleaner or similar electronics cleaner. I sprayed it over a Tupperware container, and kept spraying until there was little to no dirt or metal shavings left.



Lay out you parts, and clean them thoroughly... Spray the filter and every hole on the main part of the unit, until it looks new. Wipe everything down with shop paper towels...



Now you will need to test the solenoid. A 9v battery doesn't work (tried it) you need 12 volts.... I used an old power supply rated at 12VDC 3A...

With no power applied the piston is down...



apply power and you will see it jump.



Now pay special attention to this filter, it doesn't come off, so you have to clean it carefully but spaying the heck out of it with contact cleaner and letting everything push back through the holes. There are 16 holes, in four rows of four....



If this thing is blocked, you will have problems...

Now we start re-assembly..

There is a curved washer that acts like a small wave spring, in keeping pressure on the solenoid unit.

Take the aluminum case, put washer in then aluminum plate..





Next place spring in the bottom of solenoid, and put the plastic contact cover/plug onto solenoid and slide into case...




At this point I used a vise again as a set of hands, do not tighten too tight...

CAREFULLY Put check ball into small indentation in the dead center of the piston.
Be very careful, if you loose this ball, game over.....



Carefully put the filter/ fluid part of the solenoid onto the base. Center it, do not disturb the check ball, it should stay in its spot. Make sure you line one row of holes up centered with the connector..



Hold the unit together with your fingers, and move it from the vise, to a set of C-clamps...
lightly tighten the solenoid halves together. Be careful the goal isn't to be really tight, just to hold everything together for the next step.



In which you take a pair of channel locks and tighten the tabs that hold the solenoid together..



Then you are done, and it should be clean as new, and you know it works, as long as the filter is clean, the ball is in place, and the solenoid moves when energized.





Make sure you put on some new O-rings before you put it back in..








You just save yourself over a hundred dollars.....

Now whatever you do, don't try to take apart the Governor pressure sensor, its 100% non serviceable, so those ones you see re-furbed on Ebay, are just clean used parts.