Oil Pumps

Gear pumps handle a wider viscosity range, including heavier gear oils, with steady positive-displacement flow, and are the common choice for general oil transfer. Rotary vane pumps give smoother, lower-pulsation flow and are often chosen for lighter oils or applications where flow smoothness matters more than handling very heavy or cold viscosities.

A fixed shop dispensing station serving multiple service bays typically benefits from a higher-flow electric gear pump (10+ GPM) to minimize wait time. Field and mobile service work, or occasional smaller top-offs, are usually well served by a lower-flow hand pump or a portable 12V electric pump that doesn't require a fixed power connection.

Some gear pumps are rated across a broad viscosity range and can handle both, but flow rate drops noticeably as viscosity increases, so a pump sized for fast hydraulic oil transfer may deliver much slower flow on heavy gear oil — check the manufacturer's flow-rate-vs-viscosity chart rather than assuming a single flow rating applies across all oils.

Not necessarily by pump type, but dedicated waste oil evacuation pumps are often set up with wider intake tubes or probes designed to draw from a dipstick tube or drain, and using a separate pump (or thoroughly flushing a shared one) avoids contaminating fresh oil stock with used-oil residue and particulates.

Most Buna-N (nitrile) seals handle conventional and many synthetic oils well, but some synthetic formulations and additive packages are more aggressive toward certain elastomers — check the pump manufacturer's chemical compatibility chart against the specific oil brand and type, and consider Viton seals if compatibility is uncertain, since seal failure causes leaks and pump damage.