Yukon Ford 10.5" Ring & Pinion Gear Set - '99-'10 Super Duty
YG F10.5-355-31
The Ford 10.5" Ring & Pinion Gear Set is designed for 1999–2010 Ford Super Duty trucks, Excursions, and compatible E-Series vans equipped with the Ford 10.5" rear differential and 31-spline pinion. Whether you're replacing worn gears, correcting axle gearing after a tire upgrade, or setting up a truck for towing and off-road use, choosing the right ring and pinion ratio helps match engine power to vehicle weight, tire size, and driving conditions.
Available in 3.55, 3.73, 4.11, 4.30, 4.56, and 4.88 ratios, these gear sets give builders options for everything from highway-driven tow rigs to trucks running larger tires. Numerically lower ratios favor reduced engine RPM at highway speeds, while deeper gears increase torque multiplication to help recover pulling power lost when tire diameter increases. Proper bearing preload, backlash, and gear contact pattern are critical during installation to keep the differential running quietly and reliably under load.
Includes:
- (1) Ford 10.5" Ring Gear
- (1) Matching Pinion Gear
Note: Bearings, seals, shims, and master installation components are sold separately unless otherwise specified.
Specifications
| Product Type | Ring & Pinion Gear Set |
|---|---|
| Axle Platform | Ford 10.5" |
| Ring Gear Diameter | 10.50" |
| Axle Position | Rear |
| Pinion Spline Count | 31-Spline |
| Ring Gear Bolt Count | 12 |
| Differential Cover Bolt Count | 12 |
| Available Gear Ratios | 3.55 / 3.73 / 4.11 / 4.30 / 4.56 / 4.88 |
| Gear Configuration | Matched Ring & Pinion Set |
| Vehicle Platform | Ford Super Duty / Excursion / E-Series |
| Model Years | 1999–2010 Applications |
| Installation Type | Internal Differential Gear Replacement |
| Primary Application | Rear Axle Regearing & Gear Replacement |
Fitment
Designed for Ford 10.5" rear differentials with 31-spline pinion configurations. Verify your installed axle before ordering, as Ford used multiple rear axle platforms across these vehicle models.
| Make | Model | Year Range | Axle Application |
|---|---|---|---|
| Ford | E-250 | 1999–2010 | Ford 10.5" Rear |
| Ford | E-350 Econoline Club Wagon | 1999 | Ford 10.5" Rear |
| Ford | E-350 Super Duty | 2000–2010 | Ford 10.5" Rear |
| Ford | E-450 Econoline Super Duty | 2000–2002 | Ford 10.5" Rear |
| Ford | E-450 Super Duty | 2003–2010 | Ford 10.5" Rear |
| Ford | E-550 Econoline Super Duty | 2002 | Ford 10.5" Rear |
| Ford | E-550 Super Duty | 2003 | Ford 10.5" Rear |
| Ford | Excursion | 2000–2005 | Ford 10.5" Rear |
| Ford | F-150 | 2000–2010 | Ford 10.5" Rear - Verify Axle |
| Ford | F-250 | 1999 | Ford 10.5" Rear |
| Ford | F-250 Super Duty | 1999–2010 | Ford 10.5" Rear |
| Ford | F-350 Super Duty | 1999–2010 | Ford 10.5" Rear |
Fitment Notes:
- Fits compatible Ford 10.5" rear differentials
- Designed for 31-spline pinion configurations
- Compatible with applicable RWD and 4WD vehicles
- Verify the installed axle, pinion spline count, and selected gear ratio before ordering
- Vehicle applications are reference fitments; factory axle configurations may vary
- When regearing a 4WD vehicle, front and rear axle ratios must match
FAQ
What gear ratio should I choose for my Ford Super Duty?
The best ratio depends on tire size, engine, transmission, towing weight, and how the truck is used. Numerically lower ratios generally favor highway driving, while deeper gears provide more torque multiplication for larger tires, towing, and off-road use.
| Gear Ratio | Common Applications |
|---|---|
| 3.55 | Highway driving and stock tire sizes |
| 3.73 | Daily driving and mixed towing |
| 4.11 | Mild tire upgrades and additional pulling power |
| 4.30 | Larger tires and towing applications |
| 4.56 | Oversized tires and off-road builds |
| 4.88 | Large tires and applications prioritizing torque multiplication |
Builder Note: These are general starting points, not fixed tire-size recommendations. The correct ratio depends on the complete drivetrain and intended use.
How do I know if my Ford has a 10.5" rear axle?
The Ford 10.5" rear differential uses a 10.5" ring gear and a 12-bolt differential cover. This listing is for compatible 31-spline pinion configurations. Verify the axle identification before ordering because Ford used several different rear axle designs across its truck and van lineup.
Does this gear set include a master installation kit?
No. This listing includes the matching ring and pinion gears only. We recommend a compatible Ford 10.5" master overhaul kit when installing new gears, especially on high-mileage or heavily used axles.
Will these gears work with my existing differential carrier?
These gear sets are intended for compatible Ford 10.5" differential carriers. Confirm the carrier design, selected gear ratio, and ring gear mounting configuration before ordering. Open differentials, limited-slip units, lockers, and spools must each be matched to the correct axle and gear set.
Will changing my gear ratio help with larger tires?
Yes. Increasing tire diameter effectively raises the overall gearing, which can reduce acceleration and pulling power. Installing a numerically higher axle ratio helps restore torque multiplication and can improve drivability, especially when towing or operating off-road.
Do I need to regear the front axle on a 4WD truck?
Yes. Front and rear axle gear ratios must match on a four-wheel-drive vehicle. If you're changing the rear ratio, plan to install a matching ratio in the front differential before using four-wheel drive.
What is required for proper ring and pinion installation?
Correct pinion bearing preload, carrier bearing preload, ring gear backlash, and tooth contact pattern are essential. We recommend using a compatible master overhaul kit with new bearings, races, seals, and setup components when installing replacement gears.