The Stovebolt Site Forums The Shop Area General Truck Talk Rear End Ratio ID

I know I'll probably get drummed off the 'Bolt for this question since I'm sure it's been asked before, but a search of the archives didn't reveal the answer so here goes...How do I determine the axle ratio on a donor rear end? I remember something about counting turns on the wheel as the piion is turned? Aw #@$% I can't remember....

It's got some numbers on it (ring gear), but nothing I can clearly identify as a ratio. Can these numbers be decoded somewhere? Oh BTW, this rear end came off a '79 C-10 originally equiped with 350/350 drive train.

Sometimes the numbers on the gear are teeth count numbers, and you just divide.
If you are looking at the ring gear just count the teeth on that and the pinion, and divide, this is the most accurate method.

If you want to count turns, turn both wheels at the same time 10 turns, count pinion turns, then divide pinion turns by 10, this will be close.

Or turn one wheel 20, hold the other, and divide pinion turns by 10, close again.

Grigg

Hy Texmo, If you have the parts in your hand the ratio should be stamped somewhere on the crown [ring] gear, there should be a part number and the ratio expressed as two numbers like 37 10 that would be a 3.70 to 1 ratio, simply divide the small number into the large number, hope that helps.

Thanks guys

Like Grigg's explanation best.