help with gears.

To regear, do you just have to change the ring and pinion, or spider gears too?

 

Depending on what ratio you might have to change the carrier also.

 

I think I have 3.15s? And I want 4.10/4.11

 

Solomon, I don't know if this will help you, but I just replaced the gear oil in my '73' CJ5 and while I was doing that I checked the gear ratios and my jeep is running 3.73. 41/11. With 33" tires, I'm not sure what I should run, I'm thinking a 4.27 ratio.

 

ring and pinion but might as well get the install kit and do it right just my $.02

 

I'm runnin' 3.73's with 33 inch tires. It's no rock crawler, but fine for street use. If you are unsure about your ratio, put a mark on the driveshaft as well as the tire. Jack up the rear or have a buddy move it forward and count the number of rotations of the driveshaft until the tire rolls over once. That's your ratio. I think the only two ratio's you could get in 74 was 3.73 and 4.27 from the factory. Doubt it's 3.15 unless someone changed them, but why would they do that????

High5

 

I doubt they did. I looked on metal tag on my dana 30, and though it said 315, but I'm thinking it was old and dirty and really said 3.73.

 

The spider gears never get replaced unless you are switching to a locker. Your jeep probably does have 3.73 gears. The best way to tell is look at the number stamped on the ring gear. It will give you the number of teeth on the ring gear and the pinion gear, just divide. if you are in a hurry and you want to jack up a rear tire and count revolutions of the driveshaft compared to the tire, it will only give you an accurate reading with a locker (and both wheels in the air.) If you have a open differential the drive shaft will only take half the number of revolutions to turn a tire in the air. IE: 3.73 gears will show up as 1.86 driveshaft revolutions to one tire revolution.