Main Gearbox

Technical Description
Primary helicopter transmission gearbox for TV3-117-powered Mi-8MT/Mi-17 family configurations. It combines power from the two engines, reduces rotational speed and distributes torque to the main rotor, tail-rotor transmission and accessory drives. Gear/bearing condition, oil-system records, chip-detector history, life status and overhaul traceability are essential.

Verification Status
High – documented as the Mi-8/Mi-17 main transmission.

Source
https://vertol.com.ua/article/transmissiya-vertoleta-mi-8

Identification Note
The photograph is provided for reference. Procurement identification must be based on data plate markings, P/N, S/N, approved configuration and airworthiness documentation, not visual appearance alone.