Auto Gears Automatic Transmission Gear

Auto gears and automatic transmission gears are precision-machined power transmission components used throughout automotive drivetrains — from the engine timing gear set through the transmission layshaft and mainshaft gears, to the final drive ring and pinion, differential gears, and power take-off (PTO) gears for trucks. Korea Ever-Power Transmission Co. Ltd. produces all kinds of automotive gears including driving gears, gears for cars, light trucks, heavy-duty trucks, vans, buses, and boats — covering 40+ shaft types, 300+ driving and transmission gear varieties, planetary gears, gear rings, gear shafts, sprockets, and complete transmission gear sets such as the 1800E gearbox series for trucks.

Korea Ever-Power's auto gears include transmission gears for passenger cars, light trucks, heavy-duty trucks, and vans; motorcycle gears including transmission gears for rider motorcycles, rear transmission case gears for pedal motorcycles, startup gear sets, engine timing gear sets, and clutch gears. OEM and custom production per drawing or sample. High quality products at competitive prices.

Constant-Mesh Helical Gears

The main speed-selection gears in a manual transmission. Helical gears are used (rather than spur gears) for reduced noise at the high speeds (2,000–6,000 RPM) of car transmission mainshafts. All helical gear pairs are in constant mesh — they rotate together at all times. The dog clutch (synchromesh ring) selects which gear pair transmits torque by locking the chosen gear to the mainshaft. Tooth geometry: helical, typically 20°–25° helix angle, 20° pressure angle, M2–M4 module for passenger cars.

Automatic Transmission Planetary Gear Sets

Automatic transmissions use multiple planetary gear sets (Ravigneaux, Simpson, Lepelletier configurations) instead of layshaft gears. Each planetary set consists of a sun gear, planet gears, planet carrier, and ring gear. Different ratio stages are selected by holding one element fixed (via multi-plate clutch or band brake) while others rotate. The compact, coaxial layout of planetary sets allows multiple ratios in a small envelope — essential for the automatic gearbox's need to provide 6–10 ratios in a package no larger than a manual gearbox.

Final Drive Ring and Pinion (Crown Wheel and Pinion)

The final drive gear pair — hypoid or spiral bevel — converts the longitudinal rotation of the propeller shaft (front-engine rear-drive) or transaxle output to the transverse rotation of the drive axle shafts at the final drive ratio (typically 3.0:1 to 4.5:1 for passenger cars, up to 6:1 for heavy trucks). The ring gear is the largest gear in the driveline; the pinion is the smallest. Together they determine the vehicle's overall top speed and acceleration characteristic for a given engine and transmission ratio combination.

Engine Timing Gear Set

The timing gear set synchronises the crankshaft and camshaft(s) at the correct 2:1 speed ratio. In gear-driven timing systems (typically diesel engines and heavy-duty gasoline engines), a spur or helical gear train from crankshaft to camshaft maintains valve timing with much higher stiffness than belt or chain alternatives — eliminating timing variation from belt stretch or chain wear. Korea Ever-Power produces replacement and OEM timing gear sets for truck and diesel engine applications.

PTO (Power Take-Off) Gears for Trucks

Truck PTO gears transfer power from the transmission to auxiliary equipment — hydraulic pumps, compressors, generators, and tipping gear drives. PTO gears are typically mounted on the transmission side case and driven from the transmission countershaft. Korea Ever-Power's PTO gear range covers the standard transmission PTO interfaces (SAE 6-bolt, 8-bolt; ISO PTO shaft dimensions) and custom PTO gear sets for specialised truck-mounted equipment applications.

Heavy-Duty Truck Transmission Gears (1800E Series)

Heavy-duty truck transmissions (9, 12, 16-speed) use large-module (M4–M8) helical or spur gears on robust layshafts to handle the high torques (800–3,000 Nm) of diesel truck engines. Korea Ever-Power's 1800E gear series covers the mainshaft, layshaft, and auxiliary section gears for the 1800E heavy-duty truck transmission — a common transmission type in Chinese and export-market heavy trucks — supplying both OEM production and aftermarket replacement parts.

Rider Motorcycle Transmission Gears

4–6 speed constant-mesh spur or helical gear sets on primary, countershaft, and output shafts. Motorcycle transmission gears are typically small module (M1.5–M2.5) at high speeds (input shaft 5,000–10,000 RPM) — requiring case-carburised 20CrMnTi alloy steel with ground tooth flanks for low noise and long contact fatigue life. Korea Ever-Power produces replacement and OEM motorcycle transmission gears for common engine displacement classes.

Pedal Motorcycle Rear Transmission Case Gears

The rear transmission case of a scooter (pedal motorcycle) contains the variator-driven reduction gear set and final drive gears. These are high-speed, lightly loaded helical or spur gears in a compact plastic or light alloy case. Dimensional accuracy and noise are the primary specification drivers — Korea Ever-Power produces these to OEM drawing or from sample for scooter aftermarket suppliers.

Engine Timing Gear Set

The timing gear set synchronises crankshaft and camshaft at the engine's 2:1 cam-to-crank ratio. In motorcycle engines with gear-driven timing, precision ground helical or spur timing gears are required to maintain ignition and valve timing accuracy across the full engine speed range. Korea Ever-Power supplies both OEM and aftermarket motorcycle timing gear sets.

Startup Gear Set and Clutch Gears

The electric starter motor gear train (startup gear set) reduces the high-speed starter motor to the low-speed cranking requirement — typically 10:1 to 20:1 through 2–3 gear stages. The clutch gear is the input gear that the clutch mechanism engages and disengages to connect the engine to the gearbox. Both are precision-moulded or machined in small module (M1.0–M2.0) alloy steel. Korea Ever-Power supplies standard replacement and OEM startup gear sets and clutch gears for motorcycle engine programmes.

Passenger Cars

Manual and automatic transmission gear sets for passenger cars — main drive gears, layshaft gears, reverse gears, and synchroniser hub gears. Carburised 20CrMnTi, ground tooth flanks, DIN 6 precision. Korea Ever-Power supplies to OEM specifications for both original equipment production and aftermarket replacement.

Heavy-Duty Trucks

Multi-speed heavy truck transmission gears (1800E series and others), PTO gears, gear rings, gear shafts, and sprockets for heavy-duty trucks. Large module (M4–M8), carburised 20CrMnMo or 42CrMo, full material traceability for truck OEM supplier qualification.

Buses and Coaches

Bus transmission gear sets and final drive gears for city buses, inter-city coaches, and school buses. Bus transmission gears must handle repeated full-load starts in urban stop-start driving — the bending fatigue life requirement is more severe than for highway trucks, which motivates the use of 20CrMnMo or 20CrNiMo alloy steel for bus transmission gears.

Motorcycles

Full motorcycle gear programme: rider motorcycle transmission gears, scooter rear case gears, engine timing gear sets, startup gear sets, and clutch gears. OEM production and aftermarket replacement for Chinese and export-market motorcycle engines in 50–1,000cc displacement range.

Marine Vessels

Gears for boat gearboxes and marine reversing gearboxes. Marine gear applications require corrosion-resistant alloys or surface treatments, and robust designs for the shock loads of prop cavitation and reversing from ahead to astern. Korea Ever-Power supplies marine gear sets in stainless steel and nickel-alloy steel for seawater resistance.

Tractors and Agricultural Vehicles

Tractor transmission gears, PTO gears, and differential gears for agricultural tractors. Agricultural vehicle gears must endure shock loading from implement engagement, field surface impacts, and continuous low-speed high-torque working conditions — requiring robust alloy steel specification and adequate case depth for the large contact stresses involved.

Can Korea Ever-Power supply auto gears for specific vehicle models?

Yes — Korea Ever-Power's catalogue covers 300+ driving and transmission gear types for a wide range of vehicles. For specific vehicle model gear requirements, provide the vehicle make, model, year, and gear number/drawing — Korea Ever-Power will confirm availability from stock or production from drawing. Replacement gears produced to OEM drawing dimensions are supplied for both the original OEM market and aftermarket replacement.

What is the standard material and heat treatment for automotive transmission gears?

20CrMnTi carburised and quenched (case depth 0.8–1.5 mm, surface HRC 58–62) is the industry standard for passenger car and light truck transmission gears. Heavy-duty truck transmission gears typically use 20CrMnMo or 42CrMo for higher hardenability in the larger section sizes involved. Korea Ever-Power follows these industry standards and can adapt material specification to customer requirements including PPAP documentation for automotive OEM supplier qualification.

Can Korea Ever-Power supply both OEM production and aftermarket replacement auto gears?

Yes — Korea Ever-Power supplies automotive transmission gears for both OEM production (to vehicle manufacturer drawing and specification) and aftermarket replacement (to match original gear dimensions). OEM supply includes material certification, dimensional inspection reports, and heat treatment verification. Aftermarket supply uses reverse engineering from worn or broken sample gears when the OEM drawing is not available. Contact Korea Ever-Power with your gear specification or sample to begin.

"We are an aftermarket truck parts distributor and source 1800E transmission gear sets from Korea Ever-Power. Material certification (20CrMnMo, chemical analysis) and dimensional inspection report supplied with each batch. Carburised case depth measured at incoming: 1.1 mm average — within our 0.8–1.5 mm spec. Zero warranty claims on 48 gear sets supplied over 14 months. Price competitive with Chinese aftermarket suppliers at equivalent quality."

Kim Jae-min  |  Truck Parts Distribution Manager, Incheon Commercial Vehicle Parts Co.  ·  Q1 2026

"We manufacture motorcycle engines and source transmission gear sets from Korea Ever-Power. Reverse engineered from our existing gear sample — Korea Ever-Power produced a measured drawing and confirmed case depth spec (20CrMnTi, 0.7 mm case) before production. Noise test on our engine test bench at 8,000 RPM: 3 dB(A) reduction vs previous supplier. Sample turnaround: 9 days."

Lee Sang-min  |  Motorcycle Engine Production Engineer, Gyeonggi Powertrain Co.  ·  Q4 2025