Does anyone know what exactly will happen if an older orange overdrive relay is used in a 240 that takes the white one? I've been to my local pull-a-part and came up with just one white relay and one orange relay, and the white one is confirmed bad. I think I remember reading somewhere that with the orange relay the overdrive would work, but I would have to engage it every time I started the car via the button on the shifter? I wanted to check with some more knowledgeable people before I tried it, thanks!

 

I seem to remember having an o.d. relay issue w/ my 84 760 (orange relay). I tried the newer white one for a few moments and just remember it got quite warm very quickly so...
for $35 you could just do it right...
1985-1993 Volvo 240 Overdrive Relay