What rear end gears do I have, or how do I find out?
 

I'm thinking 3:73' s because thats what I read in some book. But my indy said that she has 4:11's in her. He has a 65 C10. So which one is it? :confused:

Re: What rear end gears do I have, or how do I find out?
 

Some times the factory will stamp the ring & pinion gear teeth on the cover. But your best bet is to pop the cover off count the teeth and divide them.

Re: What rear end gears do I have, or how do I find out?
 

Like 62 short step said, the most accurate way is to pull the cover and count the ring and pinion teeth. There should be some numbers stamped on the axle tube that indicate the original ratio, but in 40 years anything could have been changed. If you don't want to pull the cover, you can always check it by marking it. Just jack up one rear wheel, mark the tire and the driveshaft, then turn the wheel two full revolutions while counting the driveshaft revolutions. Three driveshaft revolutions = 3.00:1, three and a half = 3.50:1, etc. If your truck has a positrac rearend, you'll probably have to jack up both rear wheels and turn them one full revolution. 3.73's were the most common ratio on these old trucks, but 3.07 and 4.11 were an option. Best of luck.

60-66 Nut