OTC 2359 Oil Suction Gun, 16 oz, for Filling and Draining Gear Boxes, Transfer Cases, and Differentials

Refilling a differential, transfer case, or a manual gearbox is the job nobody warns you about. The fill plug sits on the side of the housing, an inch or two above the bottom, and there is no way to pour a bottle uphill into it. You end up wedging a tube in, squeezing a bottle, and wearing half the gear oil. This suction gun is the tool that ends that fight. You draw the fluid up into the barrel, carry it to the housing, stick the hose in the fill hole, and push the plunger to inject it right where it needs to go.

The head is aluminum die-cast rather than stamped tin, and a deluxe lip seal on the piston is what gives it the tight, strong draw that the plastic pumps never manage. The barrel holds a full 16 ounces, so on most axles and transfer cases you fill the unit in one or two pulls instead of standing there working a little syringe a dozen times. It runs both directions: pull to suck old fluid out of a differential, master cylinder, or power steering reservoir, and push to inject the new fluid back in.

It comes with a 14-inch hose to reach the fill port past the exhaust and crossmember. The hose runs on the larger side, so on a tight fill hole you can slip a short length of smaller tubing over the end to step it down, and a hose clamp keeps it seated on heavier 140-weight oil. This is a professional-grade tool from OTC, a brand that has been building shop tools for a hundred years. Buy it once and it outlasts a drawer full of the disposable plastic kind.