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Complete Third Member and Center Sections

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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!

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 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.

Individual Parts

Results 1 - 25 of 227

Center Section, Cast Iron, Ford, 9 in., Assembled, Spool, Custom Order, Dropship

Part Number: STR-PRF105

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Apr 21, 2026 if ordered today

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Estimated Ship Date: Apr 21, 2026 if ordered today

Center Section, Cast Iron, Ford, 9 in., Assembled, Posi, Custom Order, Dropship

Part Number: STR-PRF120

Not Yet Reviewed

Estimated Ship Date: Apr 21, 2026 if ordered today

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Estimated Ship Date: Apr 21, 2026 if ordered today

Center Section, Cast Iron, Ford, 9 in., Assembled, Spool, Custom Order, Dropship

Part Number: STR-PRF115

Not Yet Reviewed

Estimated Ship Date: Apr 21, 2026 if ordered today

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Estimated Ship Date: Apr 21, 2026 if ordered today

Center Section, Cast Iron, Ford, 9 in., Assembled, Spool, Custom Order, Dropship

Part Number: STR-PRF110

Not Yet Reviewed

Estimated Ship Date: Apr 21, 2026 if ordered today

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Estimated Ship Date: Apr 21, 2026 if ordered today

Center Section, Cast Iron, Ford, 9 in., Assembled, Spool, Custom Order, Dropship

Part Number: STR-PRF100

Not Yet Reviewed

Estimated Ship Date: Apr 21, 2026 if ordered today

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Estimated Ship Date: Apr 21, 2026 if ordered today

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 3/9/2026 if shipped by air

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Estimated Ship Date: Monday 3/9/2026 if shipped by air

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 3/9/2026 if shipped by air

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Estimated Ship Date: Monday 3/9/2026 if shipped by air

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 3/9/2026 if shipped by air

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Estimated Ship Date: Monday 3/9/2026 if shipped by air

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 3/9/2026 if shipped by air

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Estimated Ship Date: Monday 3/9/2026 if shipped by air

9-Inch Third Member Complete Assembly, 3.70 Gear Ratio Spool. 35 Spline, Nodular Iron Case, 1350 Yoke, Each

Part Number: CUR-CE-9SP370R50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

9-Inch Third Member Complete Assembly, 4.11 Gear Ratio Spool. 35 Spline, Nodular Iron Case, 1350 Yoke, Each

Part Number: CUR-CE-9SP411R50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

9-Inch Third Member Complete Assembly, 3.25 Gear Ratio Spool. 35 Spline, Nodular Iron Case, 1350 Yoke, Each

Part Number: CUR-CE-9SP325R50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

9-Inch Third Member Complete Assembly, 3.50 Gear Ratio Spool. 35 Spline, Nodular Iron Case, 1350 Yoke, Each

Part Number: CUR-CE-9SP350R50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

9-Inch Third Member Complete Assembly, 3.89 Gear Ratio Spool. 35 Spline, Nodular Iron Case, 1350 Yoke, Each

Part Number: CUR-CE-9SP389R50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

9-Inch Third Member Complete Assembly, 4.56 Gear Ratio Spool. 35 Spline, Nodular Iron Case, 1350 Yoke, Each

Part Number: CUR-CE-9SP456R50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

CURRIE SUPER SPORTSMAN THIRD MEMBER - 3.50 GEARS - 31 SPLINE CURRIE TWINTRAC - ALUMINUM DAYTONA PINION SUPPORT - 1350 CHROMOLY YOKE

Part Number: CUR-CE9CT350SS50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

9-Inch Third Member with 4.11 Gear Ratio & 31-Spline Currie TwinTrac®, 1350 Chromoly Yoke

Part Number: CUR-9CT411S50

Not Yet Reviewed

Estimated Ship Date: Mar 18, 2026 if ordered today

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Estimated Ship Date: Mar 18, 2026 if ordered today

9-Inch Third Member with 3.70 Gear Ratio & 31-Spline Currie TwinTrac®, 1350 Chromoly Yoke

Part Number: CUR-9CT370SS50

Not Yet Reviewed

Estimated Ship Date: Mar 13, 2026 if ordered today

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Estimated Ship Date: Mar 13, 2026 if ordered today

9-Inch Third Member with 3.89 Gear Ratio & 31-Spline Currie TwinTrac®, 1350 Chromoly Yoke

Part Number: CUR-9CT389SS50

Not Yet Reviewed

Estimated Ship Date: Mar 13, 2026 if ordered today

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Estimated Ship Date: Mar 13, 2026 if ordered today

9-Inch Third Member with 3.50 Gear Ratio & 31-Spline Currie TwinTrac®, 1350 Chromoly Yoke

Part Number: CUR-9CT350SS50

Not Yet Reviewed

Estimated Ship Date: Mar 13, 2026 if ordered today

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Estimated Ship Date: Mar 13, 2026 if ordered today

9-Inch Third Member with 3.00 Gear Ratio & 31-Spline Currie TwinTrac®, 1350 Chromoly Yoke

Part Number: CUR-9CT300SS50

Not Yet Reviewed

Estimated Ship Date: Mar 13, 2026 if ordered today

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Estimated Ship Date: Mar 13, 2026 if ordered today

Complete Third Member, 3.70:1 Gear Ratio, Detroit TrueTrac, 35-Spline, Nodular Iron Race Case, Aluminum Big Bearing Pinion Support, 1350 Yoke, Each

Part Number: CUR-CE-9TT370R50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

CURRIE PRO THIRD MEMBER - 3.25 GEARS - 35 SPLINE TRUETRAC - ALUMINUM DAYTONA PINION SUPPORT - 1350 CHROMOLY YOKE

Part Number: CUR-CE9TT325R50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

Complete Third Member, 4.11:1 Gear Ratio, Detroit TrueTrac, 35-Spline, Nodular Iron Race Case, Aluminum Big Bearing Pinion Support, 1350 Yoke, Each

Part Number: CUR-CE-9TT411R50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today

CURRIE SUPER SPORTSMAN THIRD MEMBER - 3.70 GEARS - 31 SPLINE CURRIE TWINTRAC - ALUMINUM DAYTONA PINION SUPPORT - 1350 CHROMOLY YOKE

Part Number: CUR-CE9CT370SS50

Not Yet Reviewed

Estimated Ship Date: Apr 10, 2026 if ordered today

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Estimated Ship Date: Apr 10, 2026 if ordered today