• Extremely close tolerances
• Correct alloy composition
• Correct casting and hardening    

Scania transmission require gear teeth tolerances of just thousandths of a millimetre (one-millionth of a metre) on components that bear loads equal to the weight of 20-30 tonnes concentrated on your fingernail!

These extremely high tolerances and loads mean that we put special requirements on the materials we use, the casting and hardening process, and machining and fitting precision. The steel alloy must have the right composition to guarantee correct depth and degree of hardening. Hole diameters and gear sizes must be precise, to avoid gear shearing under load. If gear tooth angles are incorrect, the risk of cracking and surface damage increases. Other problems revealed in our tests with poorly fitting parts include overheating, inadequate lubrication and the risk that the transmission seizes up.

Scania Parts are made to ensure reliable gear shifts and long service life. Many of the other parts we have tested demonstrate alarming shortcomings in materials and dimensions. For example, some synchromesh gears are made of tempered steel instead of the cast iron that we specify, leading to doubts about how well the molybdenum layer will adhere. Their outer cone angles were outside Scania tolerances and the cone surface had excessive runout, leading to scraping of gears and increased wear.

Choosing the correctly specified parts for major components like transmissions means avoiding unnecessary service or major repairs – which can make a large contribution to your bottom line.