Fluids, lubricants, and oils are an all-too-necessary set of evils that come with any vehicle. Naturally, they’re just as important as the mechanical components since they have to be able to withstand the same stresses and strains while also keeping said components safe and cool. But nothing is quite as frustrating as a busted bearing that spits shavings into an engine and ruins the whole shebang.

Similarly, it would be a real shame for transmission turmoil to ruin a perfectly good Gear Vendors Under/Overdrive. Luckily, the design of the unit makes this sad situation pretty much impossible. “It’s got its own pump. It doesn’t share anything with your transmission which is one of the big beauties of it,” says Rick Johnson, President and CEO of Gear Vendors.

The beauty lies in the fact that the GV Under/Overdrive’s fluid is completely segregated from the transmission’s lubrication system. If the transmission in front of it were to puke up its guts or overheat, the damage would not transfer to the GV unit. Since the pump’s only job is to serve the Under/Overdrive, it’s precisely engineered for that singular duty. A relief valve system designed for minimal parasitic loss means it can run at continuous duty in the most taxing of applications.

With heat and friction losses being so miniscule, 27 ounces of fluid are more than enough to handle it. In fact, the engagement solenoid that draws about 2 amps is actually the largest heat instigator. Consequently, the recommended drain and refill interval is a long 10,000 miles for standard duty. However, race cars should probably have it switched it out after each race weekend.