Overflow Tank- Trans Fluid GM 4L80E/4L85E

The Overflow Tank for Transmission Fluid GM 4L80E/4L85E by ATI Performance is an essential upgrade for serious transmission builders and high-performance enthusiasts running these legendary heavy-duty automatic gearboxes. When you're pushing a 4L80E or 4L85E transmission beyond stock parameters—whether in a drag vehicle, towing application, or heavily modified street engine—fluid expansion and thermal cycling demand proper expansion capacity that factory cooling systems weren't engineered to handle.

This dedicated overflow tank prevents costly fluid loss, maintains consistent fluid level, and protects against cavitation that can damage internal clutch and pump components. The compact, lightweight design at 1.48 lbs minimizes parasitic weight while the purposeful tank geometry promotes smooth fluid return and prevents air entrapment in the transmission cooler circuit.

This overflow tank is ideal for builders preparing vehicles for competition, aggressive street application, or maximum-effort engine builds. It is specifically compatible with GM 4L80E and 4L85E transmissions, ensuring optimal performance and reliability in demanding conditions.