[mrolds88]

Originally Posted by jd21476

So to get the drive teeth I'm going to have to open my rear diff, correct?

Not really. On a flat spot, jack up one rear wheel (after blocking at least the opposite wheel on the front. Put the truck in neutral. If the truck doesn't have a posi or limited slip, you will be able to turn the rear wheel that is in the air. If this is the case, make a mark on the tire and one on the pinion. Now turn the wheel and count how many times it turns to get the pinion to turn twice. That will give you the gear ratio. If it takes a little over 4 times to turn the pinion twice, it's 4.10's. Now if it has a posi, you will have to lift both rear wheels and turn a tire. But this time you will turn the tire as many times as needed to turn the pinion once.