Axle Code 2

Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by Tom Winkler, Sep 6, 2017.

  1. I have owned this car a few years, it is a nice little car I enjoy driving almost daily. The couple I bought it from were unable or unwilling to tell me much. What I saw is what I got. Having tended to the more stinky stuff I am touching details.
    A GPS has been the speedometer since learning its off by more than 20%. As I dug into getting the correct gear for the transmission I found a few things that don't smell right.
    First is the door tag's notation, the axle code is 2. The documentation I find has a 1, 3 thru 9. No 2. What the heck??
    Secondly, to rough guess it I lifted one wheel, marked it and the driveshaft and rotate the wheel one complete revolution. Once around on the wheel, slightly less than 1.5 revolutions of the drive shaft. I am guessing 1.4 to be more accurate.
    This car gets nearly 30 mpg cruising at 65. Out of the hole it's like a 90 year old with sticky tennis balls on his walker.
    I will take the cover off the rear end and count the teeth but geeze Louise, this is at least odd isn't it?
  2. Happily I can answer my own question. 7 1/4 inch, integral carrier, 2.83 gear rear housing that while not very well documented in anything I was able to find prior to asking my question is pretty well represented in cyberspace. I have found several sites describing rebuilding as well as adjusting the ring and pinion. I dug around in a box of 'stuff' that was in the trunk, looked like a lot of junk and after some serious cleaning it turns out I found, under the flap of the box the rear housing tag. ta-da.
    Again, why it is under represented in my shop manual, door tag decoders and other manuals I own is beyond me.
    Nuf said.
  3. Just an FYI, to get the right gear ratio by spinning the tires you have to lift both tires off the ground, mark both tires to make sure they end up at the same position and turn them at the same time or double your one wheel rotation but its best to turn both at the same time.
    imp likes this.
  4. Thank you. When I checked it following the directions I found on the internet it would have been 1.4. That couldn't be. Thinking it through instead of blocking one wheel both should turn, that's the way a car works.... or double it. That piece was not in what I read.
    Thank you for verifying. I am happiest living in a world that makes sense, its the engineer in me.
    If it's on the internet it has to be true, right? ;^}
  5. This is true, be careful with limited-slip, though. I always, for non-limited slip, raise only ONE wheel off the ground, count driveshaft turns for one tire rotation, then double the number. Both wheels off ground often give fake results due to brakes dragging, unequal movement of wheels. imp
  6. I appreciate (as my Texas sister says) all of y'all's responses. In terms of actually determining the ratio and how to do it, color me satisfied.
    As far as the code and everything I've found to decide it, well, does 2 really mean "2.83:1" or does it mean "figure it out."
    No worries either way. We live in a world where the value and integrity of information is different than when I was 12.
    Thanks again. I will have more questions and hope to learn from all of y'all.