Exmark Hydro Oil 1 Quart — Premium Hydrostatic Transmission Fluid for Lazer Z, OEM Spec

Exmark 109-9828 Premium Hydro Oil is the factory hydrostatic transmission fluid formulated for Exmark Lazer Z, Vantage, and compatible hydro systems, sold in a 1-quart container.

This genuine Exmark replacement fluid (previously numbered 1-840012) is specified for a range of Exmark commercial mowers and aerators. It’s designed to keep hydrostatic drives operating smoothly by matching the viscosity and additive package Exmark recommends. Using the correct oil helps maintain shift quality, reduce wear, and support consistent performance across demanding mowing conditions.

Which Exmark machines use this hydro oil?

109-9828 fits many Lazer Z family models and select Vantage and aerator units, but compatibility can depend on the machine’s sub-model, serial number, and production date. Always cross-check with your operator’s manual or the machine’s parts list to confirm fitment before ordering.

• Compatible series: Lazer Z, Lazer Z AS, E-, S-, X-, and Z-Series
• Also fits select Aerator 30 and Vantage models
• Replaces previous Exmark part number 1-840012
• Check serial/sub-model details against the owners manual for exact fit

How does this hydro oil support hydrostatic drive performance?

Factory-formulated hydro oil supplies the right lubrication, friction characteristics, and protection for Exmark hydrostatic transmissions. Proper fluid maintains smooth forward/reverse engagement and helps limit pump and motor wear under heavy loads. Regular use of the specified oil preserves component life and steady operation.

• Engineered viscosity and additives for Exmark hydro systems
• Reduces slippage and improves shift feel in the transmission
• Helps prevent premature pump and motor wear
• Promotes consistent performance in commercial mowing conditions

How should I use and service with this quart bottle?

The quart-sized container is ideal for top-ups, small drains, or mixing when following the service interval in your manual. For a complete hydro system change, follow Exmark’s recommended drain and fill procedure, use proper disposal methods for used oil, and torque fasteners and fill to the manufacturer’s specified level.

• Use for service top-ups or partial refills per manual guidelines
• Follow Exmark drain/fill steps and torque specs for full changes
• Dispose of used hydro oil responsibly per local regulations
• Store sealed and upright to prevent contamination

What should I check to ensure this is the right part for my mower?

Fitment can vary by sub-model and serial number, so confirm the part number listed in your machine’s parts diagram or owners manual. If uncertain, compare your existing fluid part number or consult an authorized Exmark dealer to verify compatibility.

• Cross-reference part number 109-9828 (replaces 1-840012)
• Match to model and serial number from your mower’s plate
• Consult the owners manual or an Exmark dealer for clarification
• Keep packaging or records for future service reference

Who is this for? This factory hydro oil is intended for professional landscapers, fleet managers, and serious residential owners who operate Exmark Lazer Z, Vantage, or compatible hydrostatic equipment and want to maintain OEM-recommended lubrication. If you perform routine maintenance or repair hydrostatic systems yourself and require the correct spec replacement fluid, this genuine Exmark quart is sized for service tasks and on-site top-ups. Always verify machine fitment before purchase to ensure proper application and best performance.