AMSOIL Slip Lock Differential Additive is formulated for use with both synthetic and petroleum gear lubricants and safely replaces manufacturer-recommended friction modifiers. Its convenient squeeze-tube packaging provides quick and easy application to the gear housing. One four-ounce tube of Slip Lock treats differential capacities of two to four quarts. It is not for use in automatic transmissions or other applications requiring automatic transmission fluid.
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for AMSOIL Slip Lock® Differential Additive.
Slip Lock Differential Additive is a concentrated friction-modifier supplement formulated to eliminate gear-housing chatter in cars, trucks, and SUVs equipped with clutch-type limited-slip differentials. The product works with both synthetic and petroleum gear lubricants and safely replaces manufacturer-recommended friction modifiers when the base gear oil does not already contain one.
Advanced friction modifiers for clutch-type limited-slip differentials
Clutch-type limited-slip differentials, including the Eaton Posi, Auburn cone, and similar carrier designs used by Ford, GM, and Chrysler light trucks and SUVs, rely on a thin film of friction modifier between the clutch packs to control stick-slip behavior. Without enough modifier, the clutches grab and release rapidly during low-speed cornering, producing the characteristic chatter, banging, or shudder felt through the chassis on tight-radius turns. Slip Lock is built around advanced friction modifiers that condition those clutch surfaces, restoring smooth engagement and quieting the differential without compromising the locking action that gives an LSD its traction advantage.
Squeeze-tube application for clean, accurate dosing
The product ships in a four-ounce squeeze tube engineered for quick application directly through the differential fill plug. One four-ounce tube treats differential capacities of 2 to 4 quarts of gear oil, which covers the majority of half-ton and three-quarter-ton pickup, SUV, and light-truck rear axles. The tube format reduces spillage on the axle housing and brake assemblies during top-off and makes it easy to keep a spare in the vehicle for service or fluid changes on the road.
Compatible with synthetic and petroleum gear lubricants
Slip Lock is formulated for use with both synthetic and petroleum gear lubricants and safely replaces the friction modifier specified by Ford, GM, Chrysler, and other OEMs for clutch-type limited-slip axles when the gear oil itself is not pre-friction-modified. That makes it the supported choice for refilling an LSD with a conventional GL-5 hypoid lubricant, for topping off a unit that has developed chatter after a fluid change, or for converting a unit between gear oil brands.
Designed to leave AMSOIL synthetic gear lubes alone
AMSOIL synthetic gear lubes such as Severe Gear and SAE 75W-90 Long Life Synthetic Gear Lube are built with friction modifiers and do not require this additive in most clutch-type LSDs. Slip Lock is the supported supplement only when the LSD specification calls for additional friction modifier, or when low-speed clutch chatter shows up under a fresh fill of synthetic gear oil in a mechanically sound axle. Aftermarket additives from outside the AMSOIL product line are not recommended for use with AMSOIL synthetic gear oils.
Recommended applications and service intervals
Slip Lock is intended for clutch-type limited-slip differentials in cars, trucks, and SUVs, including positraction and Trac-Lok-style axles from domestic OEMs. Match the axle, fluid spec, and capacity to the application using the AMSOIL vehicle lookup guide before dosing. The product is not intended for automatic transmissions or any application that requires automatic transmission fluid.
Add one full four-ounce tube for differential capacities of 2 to 4 quarts of gear oil. Pour through the fill plug after the gear oil has been added.
Use when refilling a clutch-type LSD with a gear oil that is not pre-friction-modified, or when an existing fill develops chatter, banging, or shudder on tight-radius low-speed turns.
Skip the additive in differentials filled with AMSOIL Severe Gear or another AMSOIL synthetic gear lube unless the axle still chatters after the new fill or the OEM specifically calls for supplemental friction modifier.
Do not use in automatic transmissions, transfer cases that call for ATF, open differentials, or any application that does not specifically require a clutch-type LSD friction modifier.
Service the additive with each gear-oil change so the friction modifier package is refreshed alongside the lubricant. If chatter returns between fluid changes and the differential has been recently filled, an additional partial dose can be added; persistent chatter after a full fresh fill with the correct dose usually points to mechanical wear in the clutch pack rather than a fluid problem.
Order AMSOIL Slip Lock Differential Additive
Master product code ADATB-EA ships as a single four-ounce squeeze tube, and ADATB-CA ships as a case of twelve four-ounce tubes for shops, fleets, and high-volume DIY accounts. Slip Lock Differential Additive is backed by the AMSOIL Limited Warranty for Lubricants. For axle application match guidance and a deeper look at the 75W-90 limited-slip-ready gear oils most often paired with this additive, see the AMSOIL vehicle lookup guide and the AMSOIL 75W-90 gear oil guide, then place an order through the Slip Lock Differential Additive product page.
This is the deal I ordered Severe Gear 75w/140 for my rear diff although sever gear comes with slip lock already added. Some have had problems with the limited slip binding in tight maneuvering so I ordered slip lock just in case of a problem. With that being said I have not had any problems/issues with diff
By Dan from WISCONSIN on April 27, 2026.
Would recommend this to a friend.
Great products
Love the things. I have ordered. Some times it takes a little to long to get the products
Does a limited-slip differential need a friction-modifier additive?
Yes, in most clutch-type LSDs. The clutch packs depend on a friction modifier in the gear oil to control stick-slip behavior on tight-radius turns. If the gear oil is not pre-friction-modified, or if the OEM specifies a separate friction modifier alongside the base lubricant, an additive like Slip Lock is required to keep the differential quiet and prevent clutch chatter under low-speed cornering.
What does Slip Lock Differential Additive do?
Slip Lock supplies advanced friction modifiers to the gear oil in a clutch-type limited-slip differential. Those modifiers condition the clutch faces so the plates engage and release smoothly under load, eliminating the chatter, banging, or shudder that mechanically sound LSDs sometimes develop after a fluid change or with a non-friction-modified gear oil. The additive does not change the gear-oil viscosity grade or the GL-5 extreme-pressure protection of the base fluid.
How much Slip Lock should be added to a differential?
Add one full four-ounce tube of Slip Lock for differential capacities of 2 to 4 quarts. That covers the majority of light-truck and SUV rear axles in service, including common Ford 8.8, GM 8.6 and 9.5, and similar Chrysler and Ram axles. Pour the tube through the fill plug after the gear oil is in place. Differentials larger than 4 quarts may require an additional dose to reach the same per-quart concentration.
Will Slip Lock hurt an open differential or an automatic transmission?
Slip Lock is formulated for clutch-type limited-slip differentials and is not intended for open differentials, automatic transmissions, or any application that requires automatic transmission fluid. It should not be poured into an automatic transmission, a transfer case that calls for ATF, or a transaxle. In an open differential it provides no functional benefit because there are no clutch packs to condition.
Is Slip Lock needed when running AMSOIL Severe Gear or another AMSOIL synthetic gear lube?
Usually no. AMSOIL synthetic gear lubes such as Severe Gear 75W-90, 75W-110, 75W-140, and SAE 75W-90 Long Life are built with friction modifiers and run quietly in most clutch-type LSDs without supplementation. Slip Lock is the supported add-pack when a specific axle still chatters after a fresh fill of synthetic gear oil or when the OEM service guidance calls for an additional friction modifier on top of the base lubricant.
Can Slip Lock be added to existing gear oil, or does the differential need to be drained first?
The additive can be added to the existing gear oil through the fill plug, provided the differential has been recently serviced and the fluid is still within its service interval. For a differential that has not been changed in a long time, the cleaner approach is a full drain and refill with a quality GL-5 gear oil followed by a fresh four-ounce dose of Slip Lock, so the friction-modifier package is paired with clean base oil rather than degraded fluid.
Does adding Slip Lock void the new-vehicle warranty?
No. Using AMSOIL synthetic lubricants or supplemental friction modifiers that meet the OEM fluid specification does not void a new-vehicle warranty under the Magnuson-Moss Warranty Act. Slip Lock is designed to replace manufacturer-recommended friction modifiers in clutch-type LSDs and is covered by the AMSOIL Limited Warranty for Lubricants when used as directed.
