ramrod thanks for the reply, unfortunately the diff has been stripped back and painted

You’ll need to remove the cover to find the ratio.

Can you show a picture of the bottom of the housing?

    Looks like something out of a 1975-1985 244

    Available ratios: 3.31:1, 3.54:1, 3.73:1, 3.90:1, 4.10:1

      ramrod ahh ok, so different to a 240 then, I need to find a couple of these as it looks like they were hacked away with an oxy, also I have to find the correct disks and handbrake pads.

      Also is this normal, when I hold the diff centre I can spin both axles with no load on them, but when I put load on the axles the diff centre will rotate both axles, would it be a LSD by chance?

      Image description

      244=240

      Definitely not LSD

      But, remove the cover to see for yourself

        I have new rotors and pads available and pad pin kits

          ramrod thanks mate, are these diffs rated as being strong compared to a Holden banjo diff? I’m looking at putting it in my HG Ute which has a stock 253 V8 in it, I have to move the leaf spring saddles out another 20mm each side to be in standard place

          • Spac replied to this.

            Just count the teeth. Put a marker pen line on a tooth then turn it counting as you go.

            My money is on 39 teeth, and 11 teeth on the pinion (from the 39 & 11 marking). Making it a 3.54, which is close to your estimation.

            In future there is no need to remove the cover, which is clearly too late here, just lock one axle and turn the pinion until the other axle completes two revolutions while counting the pinion revolutions. i use a tab of masking tape on the pinion/uni joint and on the axle/tyre to keep track of the rotations. Seems you may have done this. I have done it many times and it can be done with the diff in the car, just pop it into neutral and lift one wheel up, it only takes a few minutes.

              dmc

              I didn't know that

              Thanks for the correction

              dmc thanks for that, yeah it has 39 stamped on it, taking the cover plate off gave me a chance to clean it up 👍

              Image description

              The backing plates can be bought new, I have some that came from Skandix I think, a few years back now.

              The later diffs also had the rear wheel speed sensor for the speedo/ECU/cruise control which is located in the rear cover. This does not have it. My guess is the donor car was a mid '80s 244/240.

              The far more common ratio is 3.73:1 which is found in lots of the 240s. Not sure what ratio you are after for your project. If you are after a burnout/better acceleration diff then the 3.73 is one step shorter and the 4.1:1 gears in a 740 twin cam diff bolt right into the 240 diff and are proper short! I have those gears in my 262 and it is REAL short! Sadly still not very quick though :-( The new engine coming may fix or help that.

              Regarding an LSD a few options exist, I think VPW had an Eaton true track for about $500 or so. Plus the 400-500 to have it rebuilt-installed from a diff shop.