The Stovebolt Site Forums The Shop Area Engine Shop 3:73 ring and pinion swap

I have a 12 bolt differential with 3:73 gears. I have been considering swaping to 3:08 gears. The problem I am having is finding the correct ring and pinion for my application. I know there are several different sizes of carriers. Do I need to get a different size carrier that will accept the 3:08 gears.

I recently went through my 12-bolt 3.73 on my 63 and found the gears were mounted on a 4-series carrier. For someone like yourself that wants a higher gear ratio like 3:08, you will most likely be faced with a carrier change. If that is the case, you will have the opportunity to decide on changing over to posi if you don't currently have it. I am not a big locker fan, I have had good results with an Eaton posi unit on several vehicles.

These people were great to deal with- http://www.ring-pinion.com/
1-800-292-1031
They can supply you with any parts you need and are reasonably priced.

When I was looking into this I was told that there were two carriers made one for 3.73 and up and one for 4.11 and down. So you are most likely OK.

If you have a 12 bolt truck axle, GM parts book lists the 3.40-2.76 using the same carrier.The lower gear sets use another carrier.