Multiquip 20879 Gearbox Assembly HDA 11H - OEM Replacement Part

The gearbox assembly is the critical power transfer component located beneath the engine that converts engine output to controlled rotor speed for concrete finishing operations. This complete assembly transfers power to the rotor and governs rotational speed from 35–225 rpm through its dual-shaft design (input and output), ensuring precise blade control during float and finish passes.

In HDA Series walk-behind trowels, the gearbox receives power from the engine via a V-belt and CVT system through the input shaft, then delivers it to the rotor assembly through the output shaft. Common failure symptoms requiring gearbox replacement include clutch slipping, sluggish response to engine speed changes, difficulty rotating the input shaft by hand, worn input or output shaft bearings, or blade rotation issues. The gearbox works in conjunction with the centrifugal clutch and continuously variable transmission to achieve maximum drive torque for professional concrete finishing on surfaces up to 46 inches wide.

Compatible with the following Multiquip models:

• HDA Series Walk-Behind Trowels

Genuine Multiquip OEM part, sold by an authorized dealer.