I am currently tinkering with my uncle's 1990 740 GL w/automatic. He brought it to me to repair the overdrive. when he first got it about 2 monts ago (183,000 miles on it), the overdrive would engage after driving it for about 15 minutes. Although this is the first Volvo I have attempted to repair, I knew
about the relay problem. It had 12 volts at the connector for the solenoid, but the solenoid did not work. I replaced the solenoid with a new unit, but now the o/d will not engage at all. I still have power and the solenoid is now clicking while operating the button. I replaced both O rings on the solenoid, when the solenoid itself was replaced. The fluid has been changed recently and appears to be very clean. Is it a valve body problem or something else. Thanks for any insight.