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Complete, ready-to-run 9-inch nodular iron third member set up for 31-spline axles. Options include choice of differential type and gear ratio

***CONFIGURE OPTIONS TO SEE FULL PRICE***

SKU: CE-4026CK
Estimated Lead Time: 3-5 days
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$1,141.00

Complete drop-in Currie 9-inch third member set up for 31-spline axles. Includes choice of differential type and gear ratio, so it’s easy to build the perfect solution for your street rod, muscle car, or truck.

All Currie 9-inch third members are assembled by our in-house experts with decades of rearend setup and assembly experience so that you can trust the finished product.

 

Currie 9-inch Third Member Features:

Sportsman nodular uron gear case   Gear Case - New Currie Sportsman 9-inch nodular iron gear case with 3.062 bore carrier bearings for 31-spline axles
     
Nodular Iron Big Bearing Pinion Support   Pinion Support - New nodular iron big bearing pinion support
     
1350 Series Short Pinion Yoke   Pinion Yoke - New 1330 series short nodular iron pinion yoke
     
9-inch master Bearing Kit   Master Bearing kit - New Timken master bearing kit with seals and solid pinion spacer
     
Assembly labor   Labor - Fully assembled and set up in-house by skilled professionals

 

9-inch Third Member Options:

9-inch Ring and Pinion   Gear Ratios - Select from a wide range of ratios. Currie uses only the highest quality Motive Gear Performance® series (Orange box) ring and pinion sets
     
9-inch Limited Slip   Differential Options - Choice of 31-spline helical gear limited slip, automatic or selectable locking differentials or a steel spool

 

Differential Options Explained

Trac LockThe Trac Lock is a classic clutch-style limited-slip differential. When the unit is new, the clutches provide a torque bias that applies power to both axles equally under acceleration. When the vehicle goes around a corner, the clutches provide a limited-slip that allows the wheels to spin at different rates. Modern tire grip and high horsepower can easily overpower the clutch bias and cause the unit to behave more like an open differential that a limited-slip.  Trac Locks require periodic maintenance as normal driving wears the clutches and reduces the bias.

Truetrac and Wavetrac - Helical gear limited-slip differentials (LSD) are the modern replacement for the classic clutch-style limited-slip differential. Under normal driving conditions, HGLSDs operates as a standard or open differential, allowing one wheel to spin faster or slower as necessary without the noise or harsh operation of a clutch-style limited slip. When a drive wheel begins to slip, the helical gears inside the differential automatically engage, transferring torque to both rear wheels to maximize traction. When the wheels regain traction, the differential resumes normal operation. Unlike traditional clutch-type limited-slip differentials, HGLSDs require no special oil additive or maintenance to replace worn and tired clutches, as these units have no wearable parts, require no special maintenance, and maintain their torque bias for the life of the unit.

ARB Air Locker - Selectable locking differential, allows the driver to positively lock or unlock the differential on demand with the flick of a dash-mounted switch. As the name implies, an onboard air compressor (sold separately) is used to apply the locking force. Once locked, the differential behaves like a spool, driving both wheels equally. When unlocked, the locker behaves like an open differential, driving only one wheel at a time – usually the wheel with the least traction. The key benefits of the ARB Air Locker are its predictable behavior and legendary strength.

Detroit Locker - Automatic locking differential, designed to lock and unlock automatically when torque is applied in either a forward or reverse direction when locked, it acts like a spool driving both wheels equally.  When coasting or rolling into a corner (no torque applied), the Detroit Locker unlocks and momentarily operates like an open differential permitting the wheels to rotate freely. When torque is applied, exiting the corner, the unit locks and drives both wheels equally. The key benefits of the Detroit Locker are its rugged construction and superb performance. The only negative is that the automatic lock and unlock operation can create a clunking sensation that can be both felt and heard in the vehicle.

Spool – The spool is the simplest and strongest option, but it lacks differential action, as both axles are joined together by the spool's solid center. Spools are not recommended for the street, as the place high twisting loads on the axles, increase tire wear, and can negatively impact handling. Spools are typically only used for drag racing applications where straight-line performance is the only concern.

Complete drop-in Currie 9-inch third member set up for 31-spline axles. Includes choice of differential type and gear ratio, so it’s easy to build the perfect solution for your street rod, muscle car, or truck.

All Currie 9-inch third members are assembled by our in-house experts with decades of rearend setup and assembly experience so that you can trust the finished product.

 

Currie 9-inch Third Member Features:

Sportsman nodular uron gear case   Gear Case - New Currie Sportsman 9-inch nodular iron gear case with 3.062 bore carrier bearings for 31-spline axles
     
Nodular Iron Big Bearing Pinion Support   Pinion Support - New nodular iron big bearing pinion support
     
1350 Series Short Pinion Yoke   Pinion Yoke - New 1330 series short nodular iron pinion yoke
     
9-inch master Bearing Kit   Master Bearing kit - New Timken master bearing kit with seals and solid pinion spacer
     
Assembly labor   Labor - Fully assembled and set up in-house by skilled professionals

 

9-inch Third Member Options:

9-inch Ring and Pinion   Gear Ratios - Select from a wide range of ratios. Currie uses only the highest quality Motive Gear Performance® series (Orange box) ring and pinion sets
     
9-inch Limited Slip   Differential Options - Choice of 31-spline helical gear limited slip, automatic or selectable locking differentials or a steel spool

 

Differential Options Explained

Trac LockThe Trac Lock is a classic clutch-style limited-slip differential. When the unit is new, the clutches provide a torque bias that applies power to both axles equally under acceleration. When the vehicle goes around a corner, the clutches provide a limited-slip that allows the wheels to spin at different rates. Modern tire grip and high horsepower can easily overpower the clutch bias and cause the unit to behave more like an open differential that a limited-slip.  Trac Locks require periodic maintenance as normal driving wears the clutches and reduces the bias.

Truetrac and Wavetrac - Helical gear limited-slip differentials (LSD) are the modern replacement for the classic clutch-style limited-slip differential. Under normal driving conditions, HGLSDs operates as a standard or open differential, allowing one wheel to spin faster or slower as necessary without the noise or harsh operation of a clutch-style limited slip. When a drive wheel begins to slip, the helical gears inside the differential automatically engage, transferring torque to both rear wheels to maximize traction. When the wheels regain traction, the differential resumes normal operation. Unlike traditional clutch-type limited-slip differentials, HGLSDs require no special oil additive or maintenance to replace worn and tired clutches, as these units have no wearable parts, require no special maintenance, and maintain their torque bias for the life of the unit.

ARB Air Locker - Selectable locking differential, allows the driver to positively lock or unlock the differential on demand with the flick of a dash-mounted switch. As the name implies, an onboard air compressor (sold separately) is used to apply the locking force. Once locked, the differential behaves like a spool, driving both wheels equally. When unlocked, the locker behaves like an open differential, driving only one wheel at a time – usually the wheel with the least traction. The key benefits of the ARB Air Locker are its predictable behavior and legendary strength.

Detroit Locker - Automatic locking differential, designed to lock and unlock automatically when torque is applied in either a forward or reverse direction when locked, it acts like a spool driving both wheels equally.  When coasting or rolling into a corner (no torque applied), the Detroit Locker unlocks and momentarily operates like an open differential permitting the wheels to rotate freely. When torque is applied, exiting the corner, the unit locks and drives both wheels equally. The key benefits of the Detroit Locker are its rugged construction and superb performance. The only negative is that the automatic lock and unlock operation can create a clunking sensation that can be both felt and heard in the vehicle.

Spool – The spool is the simplest and strongest option, but it lacks differential action, as both axles are joined together by the spool's solid center. Spools are not recommended for the street, as the place high twisting loads on the axles, increase tire wear, and can negatively impact handling. Spools are typically only used for drag racing applications where straight-line performance is the only concern.

 

Selecting the right differential for your rearend build is an important decision that will be with you for a very long time - if you get it right. 

Below are short, not-too-technical, overviews of some of the most frequently asked about differential options for Hot Rods, Muscle Cars, and Muscle Trucks.

 

 

Detroit Truetrac - Helical-gear limited-slip (worm differential) is the modern replacement for the classic clutch-type posi. Under normal light throttle driving conditions, a Truetrac operates much like a standard open differential, allowing the rear wheels to rotate at slightly different speeds for smooth cornering. However, when accelerating (torque applied), the six helical-gears inside the unit smoothly and quietly engage, applying torque to both rear wheels equally, maximizing traction (think two equal length black stripes). Unlike a traditional clutch-type posi, a Truetrac requires no special oil additive or maintenance. With silky-smooth positive operation and no components to wear out, the Truetrac maintains day-one performance for the life of the unit.

 

 

     

Trac-Lok/Posi-Trac – Clutch-type limited-slip (Posi), offered as original equipment in many GM and Ford performance cars, these units rely on clutches (friction plates) to transfer power to the wheels. In operation, the clutches slip just enough to allow for smooth cornering while engaging with more force as power (torque) is applied, driving both wheels equally. When used in a daily driver, these units function well; however, as the miles add up or with aggressive driving or track use, the clutches and other internal components will become worn and severely degrade performance. Luckily, rebuild kits are widely available so that these units can be restored to like-new performance. Additionally, if the vehicle sits for extended periods, the clutch plates can stick together, causing the unit to chatter and clunk until gear oil works its way in between the clutch plates. A friction modifier must be added to the gear oil to help prevent the clutches from moaning or chattering during normal driving.
 

 

 

    

Detroit Locker - Automatic "ratcheting-style" differential is known for its reliability, rugged construction, and fully-locked performance on any surface. When power (torque) is applied in either forward or reverse directions, the unit locks both axles together like a spool. When coasting or rolling through a corner (no torque applied), the unequal speed of the inside and outside wheels causes the unit to unlock momentarily, before abruptly locking when power is applied. At the heart of the locker are two, spring-loaded forged steel side plates (one per axle) with large square-edged teeth that engage and disengage a matching center spider block. The interaction of the side plates and spider block teeth creates the signature ratcheting sound of the unit. The Detroit Locker is best suited for off-road or severe track use where maximum traction is required, and quiet/smooth operation is less important.