Forklift Transmission Gearbox Housing 120M3-82011 — Straight-Type Case for Heli CPCD20-CPCD30

The 120M3-82011 is the main transmission gearbox housing (case) for Heli CPCD20, CPCD25, and CPCD30 series 2-3 ton forklifts with the straight-type (non-offset) configuration. This is the primary structural component of the powershift transmission — all internal components including the input shaft, clutch packs, gear train, output shaft, and differential assembly are housed within this casting. The housing is cast from HT250 gray iron with a wall thickness of 8-12mm in high-stress areas around the bearing bores and 6-8mm in non-structural areas — designed to provide sufficient rigidity to maintain gear mesh alignment under full torque load while minimizing weight. The bearing bores for the input shaft, output shaft, and idler shaft are line-bored in a single CNC setup at the factory to maintain parallelism within 0.02mm across the full housing length, a tolerance that cannot be achieved by field machining and is the reason a damaged housing must be replaced rather than repaired.

Transmission housing replacement is a major repair that requires complete transmission disassembly and transfer of all internal components to the new housing. Before transferring components, the new housing must be thoroughly cleaned of all casting sand and machining debris — residual sand from the casting process, if not completely removed, will circulate through the transmission and act as a lapping compound, wearing bearing surfaces and clutch pack seals within the first 50 hours of operation. Clean all oil galleries with a rifle brush and compressed air, and verify that each gallery is clear by passing a small-diameter wire through its full length. The bearing bore diameters must be measured with a bore gauge and compared to the specification stamped on the bearing outer race — the interference fit should be 0.01-0.03mm for all main bearings. A loose bearing bore (clearance instead of interference) will allow the bearing outer race to spin in the housing, wearing the bore oversize and causing progressive gear misalignment. Common reasons for housing replacement: transmission case cracked at the engine mounting flange (overload from forklift tip-over or collision), bearing bore worn oversize from a spun bearing race, and stripped bolt threads in the valve body mounting surface that cannot be repaired with thread inserts due to insufficient wall thickness.

This straight-type housing fits Heli CPCD20, CPCD25, and CPCD30 forklifts. Verify OEM number 120M3-82011 and the housing type (straight vs offset) before ordering — the offset-type housing used on some CPCD30 variants has a 15mm offset between the input and output shaft centerlines and is NOT interchangeable. For related transmission components, visit our Forklift Hydraulic Transmission section.

Technical Specifications

• Part Number: 120M3-82011
• Housing Type: Straight-Type (Non-Offset)
• Material: HT250 Gray Cast Iron
• Bearing Bore Tolerance: 0.02mm Parallelism (Line-Bored)
• Bearing Fit: 0.01-0.03mm Interference
• Application: Heli CPCD20, CPCD25, CPCD30

Compatible Forklift Models

Each housing is pressure-tested for casting integrity, CNC-inspected for bore alignment, packed in a reinforced wooden crate, and ships within 1-2 business days. 12-month warranty. Browse our Forklift Hydraulic Transmission catalog.