12 bolt rebuild + Eaton

[DavidB]

To read the original thread and discussion on this topic go here- LINK


I am rebuilding my rear end with a new ring and pinion, seals, bearings and Eaton. The first thing I will noticed when ordering parts is the car and truck 12 bolts do not have interchangeable parts, second is they come with a 3 or 4 series carrier. The three series is for 2.76-3.42 ratio and the 4 series is 3.73+. The difference is the 4 series carrier is thicker, but they make what they call "thick" 3.73 + gears that are made to work with the 3 series carrier.
In other words if you have a three series carrier you can run any ratio. A 4 series you would be limited to 3.73+ Gears. Note: 3 series Eaton is cheaper than 4 series.
Parts I used:
Eaton 3 series #19587-010 Ebay $425
Motive gear #mgr-gm12-3.73 Summit $169
Rebuild kit #rat-3005k Summit $109