Volvo Repair: Overdrive problem, volvo 245, slow breakdown

Question
I have a 1984 Volvo 245 StWgn that is not shifting into overdrive.  I assumed
it was a problem with the automatic transmission and have just been living
with 3 gears.  I've been reading here on AllExperts and now I think I may just
have an overdrive relay switch problem.  I looked up parts on an online
swedish parts site, and think I need a Hella OEM overdrive switch.  My
husband can do the work, but I'd like to buy the right part.  There was no
slow breakdown, just one day the car did not shift into higher gears.  Do you
have any suggestions, thanks.

Answer
Rose, Start with checking fuse number 10 to see if its good.  84 should have an orange relay.  Its located behind the glove box to the left.  If its not orange then its white.   Have your husband remove the box and see which one you need.  If you replace the relay and still nothing happens then it may be the solonoid on the transmission.  If that doesnt work then there is an internal problem in the transmission.  Roger