Why would a 1988 Volvo 240 overdrive only work after a long drive of around 2 hours or more?

Answer 1

I called a shop called DaisyWagon on Ravenna in Seattle. Here's what they said. If your overdrive is working after a period of time it's a heat issue; i.e. the overdrive isn't working until something heats up. If the relay was broken, the overdrive would never work. The same thing goes for the solenoid (another "solution" on these sites)- it to is an on and off mechanism that most likely wouldn't be effected by heat. The folks at Daisy wagon most confidently said that what they do is enlarge a passageway near the diaphragm near the solenoid. After years the passageway gets to narrow and fluid won't flow through there until it is thin enough to do so at the right pressure (the speed you need for overdrive) This is why, when the fluid finally expands enough after warming up, it will activate the working solenoid and relay. If anyone has more to add to this I'd be glad to hear it- but after searching for a long time, this seemed to be a reason I could put some weight on. I'm getting the operation done on Thursday. I'll let you know how it goes.