I let my 240 sit in the freezing cold for a week. I came back and it spat out all of its oil twice (which I posted in another post). The overdrive switch is not switched on. The car won't go into fourth gear at all. I have read that it could possibly be the OD switch, wiring, or solenoid. Any ideas?

 

if the light toggles, then thje switch and OD relay are fine, so the problem is the OD solenoid, or the transmission. this solenoid is on the side of the transmission and is what tells the tranny its OK to shift into OD(4th) when it wants to.

extra fun, when the light is OUT, the solenoid is ON, and OD is enabled. when the light is ON, the solenoid is OFF and OD is disabled.

the solenoid has two O-rings. and two ports, one inside the small o-ring, and the other port between them. when the solenoid is powered, it opens the passage between these ports,. thats what allows the tranny to shift into 4th.

as a cheap (free) fix, you can remove the solenoid (clean the area around it thoroughly first), remove the o-rings, and use a dremel cutoff wheel to make a slot between the two holes, clean up all the metal filings, and all the grime, as you absolutely don't want even a speck of crud to get into the transmission's hydraulic control passages. reinstall this hacked solenoid (don't even bother to plug it back in, just hack its cord off) using just the larger outer o-ring, and see if your tranny shifts into OD... if it does, then a new solenoid will let you disable OD, or you could just leave it as it is. if it DOESN'T, your tranny OD hydraulic control circuit is probably clogged up.

 

hacked solenoid:

 

solenoid on the side of the transmission ...