Description: Works with factory 9 inch Ford differential case, ring gear, 28 spline axles, and carrier bearings, Maintenance free, no friction modifiers or special lubrication required, Quiet operation, no clicking when disengaging for corners, Provides optimum traction in forward and reverse with no clutches or springs to wear out, Instant torque feedback anytime at any speed, providing needed traction Speedway Helical-Gear Style Differential, Ford 9 Inch, 28 Spline Sku # 91909128 Mfr. Part # 91909128 Condition New Brand Speedway Motors Sold Each Details Info Fits factory and aftermarket 9-inch Ford differential housings Uses stock sized Ford 9-inch differential carrier bearings Designed for stock or aftermarket 28-spline axles Internal helical gear differential design requires no friction modifier Instant torque-biased application in forward or reverse No friction material or clutches to wear out, causing slippage Smooth operation with no ratcheting or unlocking when turning Automatically applies torque to the wheel with highest traction Works like an open differential while driving until maximum traction is needed Maximum Traction for Your 9-Inch Ford Axle Equipped Hot Rod, Muscle Car, or Truck When it comes to the venerable Ford 9-inch axle it has probably found a home under more vehicles at this point than ever came from Ford’s factories with one. The 9-inch axle is known for its great strength and has become the “go to” axle for everything from road racing and drag racing, to high horsepower street cars, and more for over half a century. Due to this popularity and demand, the Ford 9-inch axle can be built from mild to wild with all manner of parts to suit your exact needs and budget. One area that needs immediate attention for anyone considering swapping in a 9-inch axle to their build, or perhaps already has one in place, is the differential itself. While the 9-inch is the performance axle king, many of the 9-inch axles you’ll find used are in factory form and in reality, very few of the original 9-inch axles came with any sort of posi or limited slip differential (Ford used the terms Equa-Lock and Traction Lok for their version of a posi unit), especially the car-based 28-spline axle models. Taking your 2.80 geared open differential 9-inch and upgrading to a performance gear ratio and some form of limited slip-style differential will provide the best traction for your performance dollars. When it comes to performance differentials a posi unit is preferred for its ability to provide traction to both rear tires when needed. There are a lot of posi units out there with different internals that provide the same or comparable results, however, they all have their plusses and minuses when it comes to wear, noise, and cost. One of the best performing posi-style differentials of late is the helical limited slip differential. With a helical gear differential, you maintain optimum traction that is torque-biased to the wheel that can use it the most (without the other wheel spinning needlessly) and there are no friction clutch plates or springs to wear out that cause the typical slippage in high mileage vehicles. Unlike the locking differentials like the famous Detroit Locker and other similar styles, the helical gear differential does not ratchet, chatter, or click going around corners like the typical locker does as it locks and unlocks to provide differential action between the inside tire and outside tire road speeds when cornering. So, it is evident that upgrading your open differential (or a worn out factory posi) with our helical limited slip differential is the perfect solution. High Quality at A Great Value That Runs Smooth and Quiet Cast from strong 8620 steel, our helical gear differential housing is tough enough to take your engine’s power and stay together run after run. Fully machined to accept standard Ford 9-inch spec ring gears and carrier bearings, our housing is just the beginning of what we build into each helical gear differential for your Ford 9-inch build to make it the best limited slip differential. Inside you’ll find four helical pinion gears made from EN353 high strength alloy steel with a Rockwell Hardness between 58 and 60. These helical gears ride around a pair of sun gears, also called side gears (which interface with the axle’s splines). Many helical gear differentials are designed to use three pinion gears per side, we fitted ours with a fourth gear to be even stronger. In a straight line power is evenly distributed to both wheels. When turning, the helical limited slip differential allows the inside tire to turn at a slower speed due to gear separation forces. During hard acceleration, or when driving on variable terrain (one wheel on pavement the other on a dirt shoulder for example) these helical gears wedge into the machined pockets of the housing and work with the thrust forces generated by the helix angle of the helical gear teeth and the forces between the helical pinion gear and the side gear to provide more torque bias to the tire that can use it (the tire on the asphalt in our example) while still providing enough torque to the other side without slippage, providing maximum traction under any surface type or circumstance. All without any wear items to service like clutches or springs. Installs In Place of Any Ford 9-Inch Differential, Preventing the Dreaded “One Wheel Peel” Whether you are building up an all-new 9-inch axle for your project, or just looking to add some traction to an aging 9-inch you already have under the rear of your car or truck, adding our helical limited slip unit is easy. Installation is identical to servicing a stock open or limited slip/posi unit. If your current bearings are in solid shape, you can press them off your old differential and reuse them (but any doubt we encourage you to pick up new for your install). Unlike an E-locker or air locking differential, there are no case modifications required, no electrical or air compressor line to run for the helical gear differential to engage. Smooth, quiet operation is the helical gear differential’s claim to fame. You won’t even know, or be able to feel, when the helical limited slip is engaging or disengaging. It’s simply pure traction in its simplest form for your 9-inch axle. Available in 28-spline, , and versions, so if you already have performance 28-spline axles you don’t have the added expense of upgrading, but if your 28-spline axles are stock we do suggest upgrading to along with our 31-spline helical gear posi at the same time for street/strip use. For those with serious power output we suggest the 35-spline model. And don’t forget Speedway Motors has all your and a full selection of options as well. Specs Sold in Quantity Each Axle Splines 28 Bearings Included No Carrier Style Gear Style Posi MFG. Part # 91909128 Tech Support We're here to help before and after your purchase. If you have a question or need assistance with one of our products, please contact us through eBay Messaging and a knowledgeable Speedway Motors team member will be happy to help. About Speedway Motors is America’s Oldest Speed Shop® and has been a trusted source for specialty rodding and racing products and friendly expert advice for more than 72 years. Founded in 1952 by “Speedy” Bill Smith – a racer and street rodder himself – Speedway has grown from a one-man operation to become the world’s largest manufacturer, distributor and retailer of street rod and racing products. Our industry-leading fast delivery is the result of same-day shipping from our state-of-the-art, centrally located 500,000 sq. ft. headquarters. Speedway’s size offers customers unmatched product selection and low pricing, while our excellent technical support and customer service have made us a recognized leader in the rodding and racing industries.
Price: 456.99 USD
Location: Lincoln, Nebraska
End Time: 2024-12-24T13:44:17.000Z
Shipping Cost: 0 USD
Product Images
Item Specifics
Return shipping will be paid by: Seller
Returns Accepted: Returns Accepted
Item must be returned within: 30 Days
Refund will be given as: Money Back
Return policy details:
Brand: Speedway Motors
Manufacturer Part Number: 91909128
Type: Differential Carriers
Item Length: 8.40
California Prop 65 Warning: True