Complete Third Member and Center Sections

Instead of piecing one together and hoping it all fits, get a complete third member assembly with one part number from Summit Racing Equipment!

A complete third member...

Instead of piecing one together and hoping it all fits, get a complete third member assembly with one part number from Summit Racing Equipment!

A complete third member assembly (sometimes called a center section) includes everything you need to connect your driveshaft to your rear axles. They typically include a U-joint style yoke to connect to your driveshaft, ring and pinion gears, differential carrier, and a case. They’re also available with spools for maximum traction.

Whether you need a lightweight center section for racing, a trail-tough third member assembly for off-roading, or a stock replacement for fixing up your...

Instead of piecing one together and hoping it all fits, get a complete third member assembly with one part number from Summit Racing Equipment!

Whether you need a lightweight center section for racing, a trail-tough third member assembly for off-roading, or a stock replacement for fixing up your daily driver, our search tools make it easy to find the right third member assembly! For example, if you’re your looking for a Ford 9 inch third member, you can filter by case style (Ford, Chevy, Toyota, etc.), axle spline count, gear ratio, and more! With hundreds of applications available, Summit is your go-to source for complete third member assemblies.

Differential Identification Charts

Not sure what you’ve got back there? Visit Summit’s Help Center for our rear-end identification guides.

Even More Complete!

Need the matching axles, too? Consider a complete rear end assembly!

Top Brands

No third party resellers here—Summit Racing only partners with trusted manufacturers like Moser, Strange Engineering, Trail Gear, and Currie Enterprises.

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Results 1 - 25 of 143

Currie 9 in. Third Members CE-9CT370S50

Third Member, 3.70:1 Gear Ratio, Currie TwinTrac, 31-Spline, Nodular Iron Case, Big Bearing Pinion Support, 1350 Yoke, Each

Part Number: CUR-CE-9CT370S50

5.0 out of 5 stars ( 2 )

Estimated Ship Date: Monday 12/29/2025

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Estimated Ship Date: Monday 12/29/2025

Currie 9 in. Third Members CE-9CT350S50

Third Member Complete Assembly, Ford 9 in., 3.50:1 Gear Ratio, TwinTrac, 31-Spline, Nodular Iron Case, Big Bearing Pinion Support, 1350 Yoke, Each

Part Number: CUR-CE-9CT350S50

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Monday 12/29/2025

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Estimated Ship Date: Monday 12/29/2025

Currie 9 in. Third Members CE-9CT389S50

Third Member, 3.89:1 Gear Ratio, Currie TwinTrac, 31-Spline, Nodular Iron Case, Big Bearing Pinion Support, 1350 Yoke, Each

Part Number: CUR-CE-9CT389S50

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Monday 12/29/2025

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Estimated Ship Date: Monday 12/29/2025

Currie 9 in. Third Members CE-9CT411S50

Third Member, 4.11:1 Gear Ratio, Currie TwinTrac, 31-Spline, Nodular Iron Case, Big Bearing Pinion Support, 1350 Yoke, Each

Part Number: CUR-CE-9CT411S50

4.0 out of 5 stars ( 2 )

Estimated Ship Date: Monday 12/29/2025

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Estimated Ship Date: Monday 12/29/2025

Moser Engineering Ford 9 in. Third Member Assemblies 3MNC31AN370

Center Section, 9 in. Ford, Nodular Iron, Trak-Lok, 31-Spline Axle, 3.70:1 Ratio, Each

Part Number: MSR-3MNC31AN370

Not Yet Reviewed

Estimated Ship Date: Monday 12/29/2025

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Estimated Ship Date: Monday 12/29/2025

Trail-Gear Assembled Super Finish Third Members 304633-1-KIT

Third Member Complete Assembly, Assembled 29-Spline Super Finish 3rd Members For Toyota 8" Axles- V6 5.29 ARB

Part Number: TGI-304633-1-KIT

Not Yet Reviewed