The overdrive engage/disengage on the left side of the shifter sometimes works and sometimes it doesn't. The up-arrow light is on. It will go off intermittently and when it does, the RPM's are definitely lower, telling me that it will go into 4th. Am I looking at an overdrive relay problem or am I looking at an overdrive solenoid? How hard is the fix and what kind of money can I expect to pay.
Car does not shift into 4th on 1991 Volvo 740
by Boldizsar in Belleville, IL on December 19, 2010
ANSWER by Bret Bodas , December 20, 2010
There's a good chance this is the overdrive relay. Not sure how much the part is, you can find it at the dealer or online. A person with a phillips screwdriver and a little mechanical ability can replace it in 5 minutes. The relay is under the ashtray in the center console, looks like this: http://www.ipdusa.com/version.asp?strPageHistory=search&numSearchStartRecord=1&P_ID=1604&CAT_ID=0&V_ID=3506