Hi everyone,

I have a 1987 volvo 740 GLE (non-turbo) wagon with manual (m46) transmission. I can only engage the overdrive after a long time at freeway speeds. It stays in overdrive, but it won't engage when the car is cold. Do I need to replace the overdrive solenoid, relay, or both? Thanks a lot.

 

Sounds like a wiring problem. Before replacing relay/solenoid I'd check the associated wiring-it's known to do exactly what you describe.

 

Also check the transmission oil level. It should be just below the fill hole.

 

When you try to engage the overdrive does the light come on, for a while before the overdrive engages? tedv is right, the wiring is a likely culprit. However, I suffered this issue for a while myself. I always had some sort of problem with overdrive not working properly. Sometimes it simply wouldn't activate, other times the light would come on, but it would take a while for the shift to occur. I did find that some Lucas oil in the transmission provided tremendous improvement, but ulitmately all I had to do was open the relay and renew the solder joints inside to rememdy all my problems. The facts are; the overdrive units are good for quite a while, the solonoids rarely fail, the switches themselves are simple and easy to check/clean, and the electrical system controlling the overdrive is flawed everywhere between the switch and the solonoid. Take a look at the wiring and the relay, you'll most likely be able to solve your problem for a few dollars.

 

Thanks for the tips everyone. I'm going to look into it this weekend. I will start by checking the wiring and seeing if there are any obvious connection problems. I"ll also check the fluid level. As for now, I know the issue is not at the switch on the shifter, as I have tested the button, and done a wire to wire connection test. I might also see if the switch on the tranny itself needs cleaning or replacement. What makes this problem annoying is that it's intermittent. I have looked at the prongs on the relay which seem fine, but I haven't opened it up to see the internal soldered connections yet. I'll let everyone know what the outcome is. Nothing like a wild goose chase.