Eaton Detroit Locker Differential 30 Spline 1.50in Axle Shaft Diameter Rear 10.5in
The GM 10.5 inch 14-bolt full-floater is the rear axle under decades of Chevy and GMC three-quarter and one-ton pickups, Suburbans, Express and Savana vans, and countless swap builds. It is strong, but with an open carrier it still spins one tire when a loaded truck backs a trailer out of wet grass or a trail rig lifts a wheel. The Eaton Detroit Locker 225S10 is the automatic locker for that axle: GM 10.5 inch 14-bolt, 30-spline 1.50 inch shafts.
A Detroit Locker keeps both axle shafts locked together whenever the truck is under power, so both rear tires drive no matter how little grip one of them has. It does this with spring-loaded driven clutches that have coarse dog teeth instead of spider gears. When the truck turns, the outside wheel needs to go faster; its clutch ratchets out of engagement and lets it overrun, then drops back in as the truck straightens. There is nothing to switch on. Eaton's catalog note for 225S10 is specific: it replaces the conventional, non-locking differential internals only, and the factory thrust washers must be removed. That is why Eaton titles it for all ratios. It works with the gear set and carrier break you already have instead of replacing the whole case.
There are three axles people call a 14-bolt, and this part fits only one. The 10.5 inch full-floater has eight-lug hubs that stick out through the wheel, a pinion supported on both sides of the gear, and 30-spline 1.50 inch shafts held on by eight bolts at the hub. The 9.5 inch semi-float 14-bolt uses C-clips and 33-spline shafts. The AAM 11.5, which replaced the 10.5 in 2001-up 2500HD and 3500 pickups, also has a 14-bolt cover but nothing inside crosses over. Our 14-bolt vs AAM 11.5 guide and the 14-bolt problems and rebuild guide show how to tell them apart. Also note the Ram 2500 AAM 10.5 is a different axle again, so do not order this for a Ram.
Eaton's application rows for 225S10: 1972-2012 GM three-quarter-ton trucks with the 14-bolt rear and 1973-2012 GM one-ton trucks, vans, cab and chassis, motor homes and buses, with both 4.10-and-down and 4.56-and-up ratios listed. In pickups, the 10.5 ran through the 2000 model year; vans and chassis kept it longer. Count your shaft splines and confirm the 10.5 inch ring and full-float hubs, or send us the year, VIN and axle tag. Steel carrier, carrier bearings are not included. If you would rather have a full replacement case, compare the Yukon Grizzly for the 14-bolt. Other axle parts are in hard parts.
Pull the axle shafts at the hubs, remove the carrier, and take out the factory spider gears, cross shaft and thrust washers. Follow Eaton's instructions for fitting the locker into the case; check backlash and carrier bearing preload before closing it up. It is a good time to fix the 14-bolt's usual wear items: the front pinion bearing runs dry first when the oil is low, and the wheel bearings and hub seals leak with age, so an axle bearing and seal kit is worth having on the bench. A heavy steel 14-bolt cover protects the gears on rocks. If you are regearing deep at the same time, a 5.13 thick gear set needs the 4.56-and-up case. Fill with the GL-5 gear oil GM calls for in the axle; there are no clutch plates that need friction modifier. Expect clicking and a little tire chirp in tight turns, which is normal for a Detroit, and see our Detroit Locker vs Truetrac comparison if you are still deciding.
| Brand | Eaton |
| Part number | 225S10 |
| Fits | Eaton Detroit Locker Differential 30 Spline 1.50in Axle Shaft Diameter Rear 10.5in |
| Type | Differentials |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Eaton titles it for all ratios because it replaces the differential internals inside your case rather than the whole carrier. Its application rows list both 4.10-and-down and 4.56-and-up 14-bolts. Confirm your case and ratio with your axle tag if you are changing gears at the same time.
Usually not. From 2001 GM HD pickups moved to the AAM 11.5 rear, which also has a 14-bolt cover but takes different parts. This locker is for the 10.5 inch GM 14-bolt full-floater. Vans and cab-chassis trucks kept the 10.5 later, so check your axle.
Yes. When the outside wheel overruns in a turn, its driven clutch ratchets out and back in. A light click and some tire chirp in tight, slow turns is how a Detroit Locker works.
No friction modifier is needed; the Detroit Locker has no clutch plates. Use the GL-5 gear oil GM specifies for the 14-bolt.
The factory spider gears, cross shaft and thrust washers. Eaton's note says removal of the thrust washers is required. Carrier bearings are not included.
No. The 9.5 semi-float uses C-clips and 33-spline shafts. This unit is for the 10.5 inch full-float with 30-spline, 1.50 inch shafts.
