There should be TWO hairpin-type retaining spring clips in the bottom of the valve body adjacent to the broken valve. The inboard clip should
NOT be removed since it retains the piston, two springs, and the valve spool. The outboard clip (nearest the solenoid) can be removed to release what is left of the stem/body of the solenoid. Simply pull the clip straight downward out of the valve body to release the parts, then fish out what is left of the solenoid body/stem. Oil up the 'O' rings on the new valve with clean fluid, carefully align the solenoid and press it into place. Hold it in place while you insert the hairpin clip. It engages a groove on the solenoid to hold it in place.
As a further suggestion, while out shopping for parts, pick up a ½-20 oil drain plug, a ½-20 jamb nut, and a drill. Drill a ½" hole in the right rear (passenger side) corner of your trans oil pan. Remove the gasket from the oil drain plug and thread the plug from the outside through the nut on the inside of the pan. Snug it in place a weld about three good tacks around the nut flats to hold the nut in place.
Remove the oil plug, clean up any spatter, and reinstall the plug with the gasket. Most parts stores should have the plugs. I've used a lot of the Dorman/Motormite 65203 (magnetic) or 65245 (standard) plugs for this purpose. It makes service a LOT easier and cleaner.
I've found that draining the pan oil only every 20K or so removes most of the contaminants, then changing the filter every two or three drainings is more than enough to keep the trans healthy. Most sdiment and devris will be in the pan, and drain with the oil, or remain stuck to the pan magnet between filter changes. If you do a lot of towing or hauling, you may want to adjust your frequency, but the drain plug makes handling a nearly empty pan immensely easier either way.
