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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.

Not Showing Customizable Items. View Customizable Items.

Individual Parts

Results 1 - 25 of 492

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: Today

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Estimated Ship Date: 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 ( 2 )

Estimated Ship Date: Today

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Estimated Ship Date: Today

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: Today

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Estimated Ship Date: Today

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 ( 3 )

Estimated Ship Date: Today

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Estimated Ship Date: Today

Third Member Complete Assembly, ZR12, TrueTrac, 3.73:1 Gear Ratio, 33-Spline, Aluminum Case, 1350 Yoke, Each

Part Number: DSR-070650373DS

Not Yet Reviewed

Estimated Ship Date: Nov 6, 2026

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Estimated Ship Date: Nov 6, 2026

Third Member Complete Assembly, Ford 9 in., 31-Spline, Nodular Iron Case, Yukon Trak-Lok, 3.70:1 Ratio, Daytona Pinion Support, 1350 Series Yoke,Each

Part Number: MSR-3MNC31AN370

Not Yet Reviewed

Estimated Ship Date: Dec 3, 2026

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Estimated Ship Date: Dec 3, 2026

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: Nov 23, 2026 if shipped by air

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Estimated Ship Date: Nov 23, 2026 if shipped by air

FN988 STD CASE 31 SPL TT 4.10 RATIO 1350, With REM Finishing

Part Number: DSR-070880410DSR

Not Yet Reviewed

Estimated Ship Date: Nov 6, 2026 if ordered today

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Estimated Ship Date: Nov 6, 2026 if ordered today

Third Member Complete Assembly, Ford 9 in., 31-Spline, Nodular Iron Case, Detroit Truetrac, 3.50:1 Ratio, Daytona Pinion Support,1350 Series Yoke,Each

Part Number: MSR-3MST31AN350

Not Yet Reviewed

Estimated Ship Date: Dec 1, 2026 if ordered today

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Estimated Ship Date: Dec 1, 2026 if ordered today

Third Member Complete Assembly, Ford 9 in., 31-Spline, Nodular Iron Case, Trak-Lok, 3.25:1 Ratio, Daytona Pinion Support,1350 Series Yoke, Each

Part Number: MSR-3MSC31AN325

Not Yet Reviewed

Estimated Ship Date: Dec 1, 2026 if ordered today

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Estimated Ship Date: Dec 1, 2026 if ordered today

CURRIE SUPER SPORTSMAN THIRD MEMBER - 4.11 GEARS - 31 SPLINE CURRIE TWINTRAC - ALUMINUM DAYTONA PINION SUPPORT - 1350 CHROMOLY YOKE

Part Number: CUR-CE9CT411SS50

Not Yet Reviewed

Estimated Ship Date: Nov 23, 2026 if ordered today

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Estimated Ship Date: Nov 23, 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: Nov 23, 2026 if ordered today

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Estimated Ship Date: Nov 23, 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: Nov 23, 2026 if ordered today

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Estimated Ship Date: Nov 23, 2026 if ordered today

Third Member Complete Assembly, Ford 9 in., 35-Spline, Nodular Iron Case, Detroit Truetrac, 4.11:1 Ratio, Daytona Pinion Support,1350 Series Yoke,Each

Part Number: MSR-3MNT35AA411

Not Yet Reviewed

Estimated Ship Date: Dec 1, 2026 if ordered today

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Estimated Ship Date: Dec 1, 2026 if ordered today

Third Member Complete Assembly, Ford 9 in., 31-Spline, Aluminum Case, Detroit Truetrac, 3.25:1 Ratio, Daytona Pinion Support, 1350 Series Yoke,Each

Part Number: MSR-3MAT31AA325

Not Yet Reviewed

Estimated Ship Date: Dec 1, 2026 if ordered today

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Estimated Ship Date: Dec 1, 2026 if ordered today

Third Member Complete Assembly, Ford 9 in., 35-Spline, Nodular Iron Case, Wavetrac, 3.50:1 Ratio, Daytona Pinion Support,1350 Series Yoke, Each

Part Number: MSR-3MNW35AA350

Not Yet Reviewed

Estimated Ship Date: Dec 1, 2026 if ordered today

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Estimated Ship Date: Dec 1, 2026 if ordered today

Third Member Complete Assembly, Ford 9 in., 31-Spline, Nodular Iron Case, Detroit Truetrac, 3.50:1 Ratio, Daytona Pinion Support,1350 Series Yoke,Each

Part Number: MSR-3MNT31AN350

Not Yet Reviewed

Estimated Ship Date: Dec 1, 2026 if ordered today

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Estimated Ship Date: Dec 1, 2026 if ordered today

Third Member Complete Assembly, Ford 9 in., 28-Spline, Nodular Iron Case, Trak-Lok, 3.70:1 Ratio, Daytona Pinion Support, 1350 Series Yoke,Each

Part Number: MSR-3MNC28AA370

Not Yet Reviewed

Estimated Ship Date: Dec 1, 2026 if ordered today

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Estimated Ship Date: Dec 1, 2026 if ordered today

Complete Third Member, 3.50:1 Gear Ratio, Detroit TrueTrac, 35-Spline, Nodular Iron Race Case, Aluminum Big Bearing Pinion Support, 1350 Yoke, Each

Part Number: CUR-CE-9TT350R50

Not Yet Reviewed

Estimated Ship Date: Nov 23, 2026 if ordered today

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Estimated Ship Date: Nov 23, 2026 if ordered today

CURRIE SUPER SPORTSMAN THIRD MEMBER - 3.00 GEARS - 31 SPLINE CURRIE TWINTRAC - ALUMINUM DAYTONA PINION SUPPORT - 1350 CHROMOLY YOKE

Part Number: CUR-CE9CT300SS50

Not Yet Reviewed

Estimated Ship Date: Nov 23, 2026 if ordered today

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Estimated Ship Date: Nov 23, 2026 if ordered today

Third Member Complete Assembly, Detroit Speed, FN988 Assembly, 8.8 in. Gears, 31 Spline, Truetrac, 3.55 Ratio, 1350 Yoke, for Ford 9 in Housing, Each

Part Number: DSR-070880-355DS

Not Yet Reviewed

Estimated Ship Date: Nov 6, 2026 if ordered today

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Estimated Ship Date: Nov 6, 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: Nov 23, 2026 if ordered today

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Estimated Ship Date: Nov 23, 2026 if ordered today

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: Nov 23, 2026 if ordered today

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Estimated Ship Date: Nov 23, 2026 if ordered today

FORD 9'' 3.50 N GEAR 31 SPLINE TRUETRAC

Part Number: DSR-90-20015

Not Yet Reviewed

Estimated Ship Date: Nov 6, 2026 if ordered today

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Estimated Ship Date: Nov 6, 2026 if ordered today

FN988 TA CASE 31 SPL TT 3.31 RATIO 1350

Part Number: DSR-070881-331DS

Not Yet Reviewed

Estimated Ship Date: Oct 28, 2026

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Estimated Ship Date: Oct 28, 2026