PennGrade 1 Limited-Slip Gear Oil | LSD / Posi Differential | GL-5 80W-90 (27-7732-6)

PennGrade 1 Limited-Slip Gear Oil — GL-5, 80W-90 (1 qt)

A conventional gear oil with a limited-slip (LSD/Posi) additive package for differentials requiring API GL-5 specification with limited-slip friction modifiers.

Vehicle Fitment

• Limited-slip differentials: LSD and Posi-traction units requiring GL-5 spec
• Hypoid differentials: with clutch-pack or cone-type LSD units
• Not for VW air-cooled transaxles: VW boxes are GL-4 — use part 27-7729-6 instead

Why Choose PennGrade 1?

PennGrade 1 is the modern brand name for the legendary "Brad Penn" green oil — refined in Pennsylvania from paraffinic crude, long a favorite of vintage and air-cooled engine builders. Made in the USA.

Key Features & Benefits

• Limited-slip additive package: friction modifiers formulated for LSD/Posi clutch-pack and cone-type units.
• GL-5 extreme-pressure protection: for hypoid differentials under heavy load.
• 80W-90 grade: conventional gear oil viscosity.

Technical Specifications

• EMPI Part #: 27-7732-6
• Grade: 80W-90
• API: GL-5 with LSD additives
• Volume: 1 quart bottle, sold individually (case of 12)
• UPC: 707924570397
• Country of Origin: USA

Frequently Asked Questions

• Can I use this in my VW air-cooled transaxle? No. The VW transaxle is a GL-4 application — GL-5 additives can attack the brass synchros. Use PennGrade 1 GL-4 80W-90 (part 27-7729-6) in a VW box instead.
• What is the limited-slip additive for? It provides friction modifiers required by limited-slip (LSD/Posi) clutch-pack and cone-type differential units to operate correctly.

Explore Related Categories

Oils & Lubricants · Drivetrain & Transmission · Axles