ARP Automatic Transmission Cover Bolt

Why ARP Automatic Transmission Cover Bolts Are the Builder's Choice

When it comes to the fasteners that secure your automatic transmission, the stock hardware is rarely up to the task for performance builds, high-mileage rebuilds, or any application where vibration, heat, and fluid pressure conspire to work bolts loose over time. ARP (Automotive Racing Products) has spent more than five decades engineering a better answer — and their Automatic Transmission Cover Bolts are a direct expression of that philosophy applied to one of the most overlooked fastener locations on any drivetrain.

The ARP Difference: Materials and Manufacturing

What sets ARP apart from generic replacement hardware starts with raw materials. ARP manufactures fasteners from a wide assortment of materials, ranging from their proprietary "Stainless 300" alloy to 8740 chrome moly steel — both of which are nominally rated at 170,000 psi tensile strength, substantially stronger than Grade 8 hardware. For transmission cover applications, that means bolts that resist the constant thermal cycling, fluid exposure, and mechanical vibration of an operating automatic transmission far more effectively than OEM-spec fasteners.

ARP's stainless steel formulation is specially alloyed for extra durability and is virtually impervious to rust and corrosion — an important attribute wherever transmission fluid, road grime, and moisture are present. The chrome moly option is finished in black oxide for a clean, purposeful appearance that looks right at home in any engine bay.

To ensure consistency, ARP controls all aspects of the manufacturing process in-house, performing every operation from heading and heat-treat to thread rolling and shot-peening under one roof. Thread rolling — the final mechanical step — strengthens the thread roots rather than cutting material away, producing a fatigue-resistant profile that loose-fitting cut threads simply cannot match. ARP's quality systems are ISO 9001 and AS9100 registered, the same standards applied to their aerospace fastener division.

Vibration Resistance and Secure Fitment

Transmission cover bolts live in an environment defined by vibration. ARP's vibration-resistant fasteners provide more reliability than OEM, and kits typically come complete with washers to ensure proper load distribution across the cover surface and prevent distortion or leaks. The application-specific nature of ARP's design means correct thread pitch, diameter, and under-head geometry for your particular transmission — no guessing, no improvising.

Available in your choice of polished stainless steel or black oxide finished chrome moly, and with both standard hex and 12-point head configurations, ARP transmission cover bolts let you match the hardware to the build — whether you're after the clean look of polished stainless on a show car or the understated strength of black oxide on a race-day warrior.

Trusted by the Best Builders in the Business

There's a reason virtually every top professional builder relies on ARP fasteners — from NHRA and NASCAR to Formula 1 and IndyCar. That same engineering rigor flows directly into every transmission cover bolt ARP produces. For the enthusiast building a high-performance automatic transmission, or simply executing a quality rebuild that won't be touched for years, upgrading to ARP means one less potential failure point in the driveline.