The HMMWV has a complex transmission system with an automatic transmission, transfer case and four-wheel drive. The transmission inspection begins with a diagnosis of shifting, noise and slippage. Next, the quality of the transmission fluid is checked for chips or overheating.

After dismantling the gearbox, disassembly and detailed diagnostics of all components are carried out: gears, clutches, hydraulic unit, torque converter. Worn elements are replaced, channels are flushed and pressure is adjusted. The software is also updated or adaptation is carried out after repair.

The transfer case undergoes a separate inspection for wear of synchronizers, gears, bearings. After assembly, the components are checked for tightness and operability in dynamic mode, including switching 4x2/4x4 modes.