Hi, This is my first post but Ive been a 240 driver for many moons. Now Im stumped with a problem that sadly has a history. Im sorry, this is a little long.

About 6 years ago, the transmission started slipping and shortly thereafter, the car stopped moving. I had it fixed at a local shop that has been in the tranny fixin business for, well, at least 30 years. A guy I havent seen in 20 years but knew in HS fixed it. He was a nice enough guy then. He was an employee at this family owned shop. A few days later it was fixed, I paid $1200, got a 1 year/12K warranty, and off I went. All is right with the world.

The twist: The problem (that I describe next) began about 18mos later. I talked to the owner, real nice guy, told him about the initial repair, that my friend worked on it, and right then, before I could describe the current situation, he said "******, isnt any friend of mine!! He's gone! When he was working here, he was fixing MY customers cars, giving them MY warranty, and KEEPING all of the money!"

Well OK then...here are the symptoms, Volvo Drs:

The car was (and still is) shifting correctly until its OD time. This is the unusual part: Depending upon the temperature of "something", of which Im POSITIVE involves the time of year, it will eventually shift into OD, and once there, it will shift great all the time. Starts, stops, highway, hills, town...but once that "thing" cools down, always due to it being parked for some amount of time, , its back to no OD. The OD button/switch also has no effect when the thing isnt shifting right, and works perfectly well when it is. I can hear the relay clicking regardless of what the OD seems to be doing and the "up" arrow" lights/unlights quickly whenever the switch is pressed. I had to replace that about 8 years ago.

Summertime is the shortest running time for everything to work, followed by spring and fall, last is winter. Im talking about the amount of time, distance, and speed I have to drive before it shifts into OD Sometimes in winter, on really cold days, it wont ever hit OD. Other than those rare frigid days, it will ALWAYS end up working properly, sooner or later. And even when the OD finally kicks in, it will be a smooth shift, no jerks, noises, or anything unusual, it engages and continues to work just as though it always did.

The car, including the tranny, drips nothing, burns nothing, and the tranny fluid isnt mysteriously disapearring nor does it look cloudy or smell funny. Except for the air conditioning and minor electrical issues (Yep, typical 240) this car is very reliable, even with this problem that Ive had for about 4 years. The problem is just as reliable, every time, no OD, just drive a while, you get OD.

So here are my ideas:

The OD soleniod (or wires)
The OD relay
My buddy goofed something up inside the tranny.
He used the wrong viscosity of tranny fluid.

The fact that the temp is affecting this makes me think the fluid is wrong. But I also dont know what the solinoid touches or slides into (does it move at all)? If not, could it be the thing that is activated by it? Is there any oil/lubricant in the solinoid that might warm as driving continues? I have a new soliniod coming but Id rather not have to play a guessing game.

Thanks again for your ideas.