Aside from taking apart my rear end, how would I determine which rear end gears my 72 challenger has? I was under the assumption on my fender tag it would have a code D "72 thru 85" ? I have a D34 and then nothing until code E44. Any ideas? maybe I am just reading the codes wrong.... Thanks

Likely 3.23's. Raise the rear and count the driveshaft rotation vs 1 rotation of the wheels.

This only works if it is a sure grip, an open rear can not be counted by this method.

Does the speedo read correct? If it does remove the gear and see how many teeth it has. What is your rear tire size. Do you have an aftermarket tachometer? What is your RPM at 60 MPH?

Your rear end should have a little metal tag bolted to it that will have the ratio. Also the bottom of the carrier should be marked with wide stripes that also tell the ratio.

The gear ratio codes are not on the fender tag because they have nothing to do with how the body is built or painted.

I think it still works with an open if you leave one wheel on the ground