I need to verify the location of the OD solenoid on my 88 240 AT wagon. I found a wire that is routed from the right rear of the trans in the area of the fluid pan and drain, over the top to the left rear, and terminating at the top of a vertical cylindrical structure secured by two bolts to the left of the fluid pan. I assume this cylindrical structure is the solenoid. I didn't see any significant deterioration of the wire. Over a period of about 10 days the car completely lost 4th gear. The transmission, including fluid quality and level, seems fine otherwise. At first the problem was intermittent. The dashboard arrow always goes on and off with the gearshift switch. From what I could glean from old NG articles I assume this means the relay is good. My idea is to check whether voltage to the solenoid goes on and off with the switch and if so I will assume the solenoid needs replacing. Is this a reasonable strategy?