Originally Posted by lbram81
I have the 3.55 with anti slip rear diff
My axle tag says 3.55 along with my build sheet and window sticker
My wife being a smart ass on our farm the other day spun the rear tires in the grass and both rear tires left a patch so I'm convinced anti slip is there.
That's how I determined my setup.
I need to do that with mine as well just to verify.
Regarding the exact ratio, you need to raise the rear of the truck up enough to get both rear wheels off the ground, mark a spot on your tire and your driveshaft (ensure vehicle is in neutral obviously and chock wheels and use axle stands) sping your tire and while doing so, keep an eye on your driveshaft, it should go around almost 4 times or in your case 3.92 times.