The Stovebolt Site Forums The Shop Area Engine Shop Rear-Gear Ratio

First of all, Merry Christmas!. Second, I am trying to figure out what the gear ratio of my 60 GMC is. I jacked up that back end, marked the driveshaft, marked the wheel. Here is where I am confused, for every full rotation of the wheel, the driveshaft rotates twice. I thought the driveshaft should rotate close to four times for a 3.90 or 4.10 ratio. Am I doing something wrong? Another thing, if only one wheel rotates at a time, do I have limited slip? I thought that if one rotates one way, and the other wheel goes the other way, that means you don't have limited slip. Is that true? Thanks!

Merry Christmas, firstly if only one wheel turns it's not a limited slip [very rare option in those days]. Secondly you are overlooking the differetial gears themselves, those are the gears that allow the two axles to turn at different speeds when you go around a corner. If when doing your test only one wheel turned, you can basically double your driveshafts number of turns giving you a ratio of 4 to 1, hope this helps.

Thanks! The reason I thought it was limited slip was that behind the seat on the cardboard covering, the is a sticker that say something about "this vehicle is eqquiped with a limited slip differential...."..a cation sticker. So basically I have a 3.90 or 4.10 gear set then? Your explination makes sense. Thanks!