DSE FN988 REM Polished Center Section - 3.31 Ratio / 31-Spline Truetrac - 070880-331DS-R
Combine the proven packaging of a traditional Ford 9-inch housing with the quieter, more efficient operation of an 8.8-inch gearset with the Detroit Speed 070880-331DS-R FN988 Assembled Center Section. Detroit Speed's patent-pending FN988 design allows an 8.8-inch center section to bolt directly into a traditional 9-inch housing, giving performance builders an alternative to the gear noise and efficiency losses associated with conventional 9-inch components. This REM-polished version comes completely assembled with a 3.31 gear ratio, 31-spline Eaton Truetrac differential, and 1350 forged-steel pinion yoke with U-bolts.
The REM-polished gearset takes the 070880-331DS-R another step toward reduced friction and efficient operation. Detroit Speed states that the REM process creates a smooth micro-textured surface that enhances oil retention while reducing heat and friction, increasing component life, and promoting quiet operation. The assembly is built around a high-strength nodular cast iron case with forged alloy-steel carrier bearing caps, a premium ring and pinion secured with safety-wired ARP ring bolts, a solid pinion preload spacer, and internal oil channels that provide continuous lubrication to the pinion bearings.
Specifications
- Manufacturer: Detroit Speed
- Part Number: 070880-331DS-R
- Product Type: Differential Assembly
- Case Series: FN988
- Carrier Style: Ford 8.8-inch
- Case Material: Nodular Iron
- Differential: Eaton Truetrac
- Axle Shaft Spline Quantity: 31
- Gear Ratio: 3.31
- REM Polished: Yes
- Yoke Style: 1350
- Pinion Yoke: Forged Steel
- Yoke Hardware: U-Bolt Kit
- Universal 9-Inch Center Section: Yes
- Application Specific: No
- Emissions Code: 4
Features
- Patent-pending FN988 design utilizes an 8.8-inch gearset in a traditional Ford 9-inch housing
- 3.31 gear ratio
- 31-spline Eaton Truetrac 8.8-inch differential
- REM-polished gearset for reduced heat and friction
- REM treatment creates a smooth micro-textured surface to enhance oil retention
- REM process is designed to increase component life and promote quiet, efficient operation
- High-strength nodular cast iron case
- Premium ring and pinion with safety-wired ARP ring bolts
- Internal oil channels provide continuous lubrication to the pinion bearings
- Solid pinion preload spacer
- Forged alloy-steel carrier bearing caps
- 1350 forged-steel pinion yoke with U-bolt kit
- Threaded jack-bolt holes in the mounting flange help ease center-section removal from the axle housing
- Case includes mounting holes for bolt-on accessories
- FN988 case is compatible with 8.8-inch gears, differentials, and spools
Fitment Notes
The Detroit Speed 070880-331DS-R is a universal FN988 center section and is not assigned to a specific year, make, or model. It is designed to bolt into a traditional Ford 9-inch housing while utilizing Ford 8.8-inch differential components. Detroit Speed specifies that FN988-specific axle shafts are required and the driveshaft will need to be shortened. Verify the complete rear axle and driveline combination before installation.
FAQs
What is the difference between 070880-331DS-R and 070880-331DS?
Both versions use a 3.31 gear ratio, 31-spline Eaton Truetrac differential, and 1350 yoke, but 070880-331DS-R features REM-polished gears. Detroit Speed states that REM treatment reduces heat and friction, increases component life, and promotes quiet, efficient operation.
What does REM polishing do to the FN988 gearset?
The REM polishing process creates a smooth micro-textured gear surface with enhanced oil-retention properties. Detroit Speed identifies reduced heat and friction, increased component life, and quieter, more efficient operation as benefits of the treatment.
Does Detroit Speed 070880-331DS-R require FN988-specific axle shafts?
Yes. Detroit Speed specifies that FN988-specific axle shafts are required. The driveshaft will also need to be shortened for the FN988 installation.
Why Buy Detroit Speed from Beefcake Racing?
Beefcake Racing is your source for Detroit Speed rear axle, suspension, chassis, and drivetrain components for serious street, pro-touring, autocross, and track builds. Building an FN988 rear end requires matching the center section with the correct axle shafts, housing, and driveline components, and our team can help you put together the right combination. Questions about Detroit Speed 070880-331DS-R or your FN988 rear axle setup? Email sales@beefcakeracing.com or call 1-855-827-7223.
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