Under the grime on my 84 GL there's a sticker glued on the rear axle's back side about midway between the left wheel and the differential. It was covered with rust proofing and years of grime and paint thinner exposed it. I have an 84 with 3.31 rearend which was supposedly used only in diesels. This car has been to traffic court at least three times with other speeding tickets in the interum. I finally had the speedo certified and at 65 you were really going 75. I tried to change the speedo cable's drive gear but of the three available the car already had the one giving the lowest mph reading. Volvo suggested the overdrive had the wrong worm gear. The previous owner had oversize tires and that added to the problem.

Good Luck!

Steve L 3- 240's in Charlotte, NC