Forklift Transmission Gasket & Shim Set — Precision Sealing for Gearbox Flange Joints

This transmission gasket and shim set is designed for forklift gearbox flange joints, providing both fluid sealing and precision axial clearance adjustment in a single assembly. Unlike standard paper-based gaskets that compress unpredictably under bolt torque, these shim-gaskets are manufactured from multi-layer steel (MLS) with a controlled-thickness elastomer coating on each face — typically 0.25mm, 0.50mm, or 0.75mm total thickness depending on the application. The critical function is twofold: the gasket prevents ATF or gear oil weepage at the gearbox-to-bell-housing or gearbox-to-torque-converter flange interface, while the precise shim thickness sets the input shaft axial end-play to factory specification (typically 0.05-0.10mm for forklift gearboxes). Using a generic paper gasket of incorrect thickness will either over-compress (causing oil leakage) or be too thick (causing input shaft thrust bearing overload and premature failure within 500 hours).

Installation of a transmission shim-gasket requires absolute cleanliness of both flange faces — any residue from a previous gasket, even a 0.02mm film of old gasket compound, will alter the effective shim thickness and throw off the axial clearance measurement. Use a plastic scraper only; steel scrapers will score the aluminum or cast iron flange surface and create leak paths. Apply a light coat of transmission assembly lube to the gasket faces before installation — this allows the gasket to settle evenly under bolt torque without binding or tearing. The flange bolts must be tightened in a star pattern to 35-40 N·m (±3 N·m) in two stages: first to 50% torque, then to full torque. Never use RTV silicone sealant on a shim-gasket — the silicone film thickness is uncontrolled and will alter the shim’s effective thickness by 0.05-0.10mm, which is the entire tolerance range for input shaft end-play. Common failure symptoms: a slow ATF drip at the bell housing flange (gasket compression fatigue), a humming noise from the transmission that changes with temperature (input shaft bearing preload due to incorrect shim thickness), and transmission fluid contamination with clutch material (seal failure allowing debris migration between fluid chambers).

This shim-gasket kit fits Heli CPCD15-CPCD50, Hangcha CPCD15-CPCD50, and TCM FD15T-FD50T forklift gearbox flange interfaces. Before ordering, measure your existing gasket thickness with a micrometer — the shim thickness is your only definitive fitment reference. For related gearbox sealing components including input shaft seals, output shaft seals, and O-ring kits, visit our Forklift Mechanic Transmission section. For OEM technical documentation, refer to the Heli Official Website.

Technical Specifications

• Part Type: Transmission Gearbox Shim-Gasket (MLS)
• Material: Multi-Layer Steel + Elastomer Coating
• Available Thicknesses: 0.25mm, 0.50mm, 0.75mm
• Function: Fluid Sealing + Axial End-Play Adjustment
• Flange Bolt Torque: 35-40 N·m (Star Pattern, 2-Stage)
• Compatibility: Heli/Hangcha/TCM 1.5-5T Gearbox Flanges

Compatible Forklift Gearboxes

Each gasket set is sealed in rust-preventive packaging and ships within 1-2 business days. 12-month warranty against manufacturing defects. For bulk orders or custom thickness specifications, contact our team. Browse our Forklift Mechanic Transmission catalog for more drivetrain components.