SKU: BPO77296
UPC: 816558021400
MPN: BPO77296
This PennGrade Motor Oil 80W-90 Hypoid Gear Oil is a 1-quart, GL-4 mineral-based lubricant built for classic manual transmissions and driveline components that call for GL-4 protection rather than the more aggressive GL-5 additive package. Unlike many hypoid fluids aimed at high-load hypoid differentials, this formulation is intentionally tuned for synchronizers, bushings, and thrust washers made from yellow metals such as brass, bronze, and copper. If you're maintaining a vintage transaxle or a synchro-equipped gearbox, this is the kind of gear oil that protects those soft metals without attacking them. Find it and related fluids in our oils, fluids and sealer selection.
The 80W-90 viscosity grade covers a broad temperature range, staying fluid enough for cold-weather shifting while holding film strength under load at operating temperature. PennGrade builds this Classic GL-4 fluid from premium mineral base stocks with select additive technology, and it deliberately omits limited-slip friction modifiers and the high-sulphur extreme-pressure additives common to GL-5 oils. That matters because aggressive GL-5 chemistry can corrode the brass and bronze synchronizers found in older gearboxes. The GL-4 specification here, per manufacturer specifications, targets exactly those soft-metal components. The result is a gear lubricant matched to the metallurgy of classic transmissions, not a one-size-fits-all bottle. For GL-5 driveline needs, we stock heavier 85W-140 gear oil and other grades separately.
Reach for this PennGrade hypoid gear oil when a manual transmission or transaxle calls for a GL-4 fluid in an 80W-90 grade. It's a common requirement on classic trucks, sports cars, and older domestic and import gearboxes with brass synchronizers. Always confirm the GL-4 versus GL-5 callout for your application before filling, since the two are not interchangeable in synchro-equipped units. Buyers topping off a differential or running a separate transmission spec can compare our 75W-90 gear oil and our broader grease options for the rest of the driveline.
Hypoid gear oil is a gear lubricant designed for the sliding, high-pressure contact found in hypoid and other heavily loaded gear sets. This PennGrade product carries the 'Hypoid' name to describe its intended driveline use, but it is a GL-4 formulation built for synchronizer-equipped manual transmissions rather than the GL-5 chemistry used in many hypoid differentials.
No. GL-4 and GL-5 are not interchangeable. GL-5 oils carry a more aggressive extreme-pressure additive package suited to hypoid differentials, while GL-4 is formulated to protect the brass and bronze synchronizers in manual transmissions. Always match the specification your gearbox or differential calls for.
Per manufacturer specifications, this Classic GL-4 oil is designed for yellow metallurgy such as brass, bronze, and copper used in synchronizers, bushings, and thrust washers. It omits the high-sulphur additives that can corrode those soft metals over time, making it suited to classic manual transmissions and transaxles.
This is an 80W-90 multigrade gear oil supplied in a 1-quart bottle. The 80W-90 grade stays workable in cold weather while maintaining film strength under load at operating temperature.
No. This formulation does not include limited-slip friction modifiers. If your application requires a limited-slip additive package, choose a fluid specifically labeled for that use or add the correct friction modifier per your equipment's requirements.
WARNING ⚠️ You must be 18 or older to purchase shotgun or rifle ammunition and 21 or older to purchase handgun ammunition and firearms. Please reference our requirements for ammunition orders to "restricted" states HERE. Always make sure you use the correct ammunition for your firearms. Ammo cannot be shipped to a PO Box. Please reference state & local laws before making a firearm or ammunition purchase.
