Yukon Chrysler 8.75" Steel Full Spool - 30 Spline
YP FSC8.75-30
The Yukon Chrysler 8.75" 30-Spline Steel Full Spool replaces the factory differential carrier with a solid connection between both axle shafts, keeping both wheels locked together at all times. Unlike an open differential or automatic locker, a full spool eliminates differential action entirely, making it a popular choice for drag racing, mud racing, rock crawlers, and dedicated competition vehicles where consistent traction and drivetrain strength matter most.
Manufactured from heat-treated 8620 steel, this Yukon spool is built to handle aggressive launches, high horsepower, and repeated drivetrain shock loads without the clutches, springs, or engagement mechanisms found in traditional lockers. Designed for Chrysler 8.75" differentials with 30-spline axle shafts, it works with compatible 741, 742, and 489 case configurations and uses standard LM104949 carrier bearings and LM104912 races. It's a simple, durable solution for builders who need a permanently locked rear axle.
Includes:
- (1) Yukon Chrysler 8.75" 30-Spline Steel Full Spool
Installation Note: Carrier bearings, races, installation hardware, and differential setup components are not listed as included. Verify the required components for your axle before installation.
Specifications
| Manufacturer | Yukon Gear & Axle |
|---|---|
| Part Number | YP FSC8.75-30 |
| Product Type | Full Differential Spool |
| Axle Platform | Chrysler 8.75" |
| Axle Spline Count | 30-Spline |
| Material | Heat-Treated 8620 Steel |
| Traction Type | Permanent 100% Lockup |
| Differential Action | None |
| Carrier Replacement | Yes |
| Compatible Case Configurations | 741 / 742 / 489 |
| Carrier Bearing Number | LM104949 |
| Carrier Race Number | LM104912 |
| Axle Position | Rear |
| Installation Type | Differential Carrier Replacement |
| Primary Application | Racing & Competition Drivetrain |
| Street Use | Not Recommended |
| Quantity | Sold Individually |
Fitment
Designed for Chrysler 8.75" rear differentials using 30-spline axle shafts. Compatible with 741, 742, and 489 case configurations. Verify the installed axle before ordering, as factory axle equipment may vary by vehicle.
| Make | Model | Year Range | Axle Application |
|---|---|---|---|
| Chrysler | Imperial | 1961–1973 | Chrysler 8.75" Rear |
| Chrysler | New Yorker | 1961–1973 | Chrysler 8.75" Rear |
| Dodge | A100 Truck | 1964–1970 | Chrysler 8.75" Rear |
| Dodge | B100 Van | 1971–1974 | Chrysler 8.75" Rear |
| Dodge | B200 Van | 1971–1974 | Chrysler 8.75" Rear |
| Dodge | Challenger | 1970–1973 | Chrysler 8.75" Rear |
| Dodge | Charger | 1966–1973 | Chrysler 8.75" Rear |
| Dodge | Coronet | 1965–1973 | Chrysler 8.75" Rear |
| Dodge | Dart | 1961–1973 | Chrysler 8.75" Rear |
| Dodge | Monaco | 1965–1973 | Chrysler 8.75" Rear |
| Dodge | Polara | 1961–1973 | Chrysler 8.75" Rear |
| Dodge | D100 Series / D100 Pickup | 1961–1973 | Chrysler 8.75" Rear |
| Dodge | D200 Series / D200 Pickup | 1961–1973 | Chrysler 8.75" Rear |
| Dodge | D300 Series / D300 Pickup | 1962–1968 | Chrysler 8.75" Rear |
| Dodge | W100 Series / W100 Pickup | 1960–1973 | Chrysler 8.75" Rear |
| Dodge | W200 Series / W200 Pickup | 1960–1973 | Chrysler 8.75" Rear |
| Plymouth | Barracuda | 1964–1974 | Chrysler 8.75" Rear |
| Plymouth | Belvedere | 1963–1971 | Chrysler 8.75" Rear |
| Plymouth | Duster | 1970–1973 | Chrysler 8.75" Rear |
| Plymouth | Fury | 1961–1973 | Chrysler 8.75" Rear |
| Plymouth | GTX | 1967–1971 | Chrysler 8.75" Rear |
| Plymouth | Road Runner | 1968–1973 | Chrysler 8.75" Rear |
| Plymouth | Satellite | 1965–1973 | Chrysler 8.75" Rear |
Fitment Notes:
- Fits Chrysler 8.75" differentials with 30-spline axle shafts
- Compatible with 741, 742, and 489 case configurations
- Uses LM104949 carrier bearings and LM104912 bearing races
- Verify axle model, spline count, ring gear compatibility, and carrier dimensions before ordering
- Intended for dedicated racing and off-road competition applications
FAQ
What does a full spool do in a Chrysler 8.75" differential?
A full spool replaces the differential carrier and locks both axle shafts together permanently. Both wheels turn at the same speed regardless of traction, making it a simple way to maintain drive to both tires during racing and off-road competition.
Is a steel spool stronger than an automatic locker?
A spool is generally one of the simplest and strongest differential configurations because it has no internal clutches, springs, or engagement mechanisms. It eliminates the moving components found in automatic lockers, making it a popular choice for high-horsepower and high-shock-load applications. Overall axle strength still depends on the shafts, gears, housing, and complete drivetrain.
Can I use this Chrysler 8.75" spool on the street?
We do not recommend a full spool for regular street use. Since both axle shafts are permanently locked together, the tires cannot rotate at different speeds during turns. This causes tire scrub, increased wear, additional drivetrain stress, and changes in vehicle handling on pavement.
What axle shafts does this Yukon spool require?
This spool is designed for Chrysler 8.75" axle assemblies using 30-spline axle shafts. Verify the spline count of your existing shafts or replacement axle shafts before ordering.
Will this spool fit Chrysler 741, 742, and 489 differential cases?
Yes. This spool is listed for compatible Chrysler 8.75" differential assemblies using 741, 742, and 489 case configurations. Confirm the installed carrier, bearing dimensions, and ring gear compatibility during your build.
What bearings does this spool use?
The Yukon Chrysler 8.75" steel spool uses LM104949 carrier bearings with LM104912 bearing races. These are separate service components unless specifically included in your purchase.