Why is the choice of gear oil important?


What difference does it make, which oil is used in the gearbox? Well, the transmission system i.e., the gearbox and final drive, provides the indispensable link between the power unit and the drive wheels. It is the job of the gearbox to multiply the torque coming from the power unit, whilst the differential multiplies the torque – supplied by the gearbox – again, and distributes it across the driven axle.


The transmission system has to do all of this under the harshest of conditions i.e., high ambient temperatures and freezing conditions, at low-speeds and high-speeds, and with forces being constantly transmitted back and forth through the system. The operating conditions that a gearbox, final drive or transaxle has to deal with are demanding and, with the wrong gear oil or degraded oil, levels of wear can skyrocket.


For instance, a typical 15-kilometre journey across a busy city produces, on average, around 85,000+ gear changes and 17,000+ stop-starts per year. Driving conditions in the city, with repeated stop-start cycles, place the transmission system and lubricant under enormous stress. Ordinary gear oils degrade, simply breaking down under such demands.


Added to these stress factors is the development that vehicles are getting heavier every year. Increased vehicle weight correlates directly to increased loading of the transmission unit and raised mechanical and thermal stress for the gear oil. Gear oil maintenance is therefore critical to ensuring drivetrain longevity and maintaining fuel economy.


Despite advances in tribology and lubricant technology in general, the demands placed on gear oils – both thermal and mechanical – mean that regular replacement is necessary; even if not explicitly stipulated in a manufacturer’s service schedule.


Selecting a high-quality product and ensuring that the oil is chosen according to the application and manufacturer’s specification, is as important as adhering to the recommended replacement interval.

Manufacturers usually specify a standard, minimum-quality oil, but the actual quality of the product used in service is decided by the customer. Cheaper oils often lack high-quality additives, which improve fluidity at low temperatures and prevent premature ageing. Here is where spending a bit more on a higher quality product can make a significant difference.


Criteria such as the ability to withstand repeated extreme-pressure loading, provide lubrication across a wide range of temperatures and, of course, the capability to ensure a reliable high-strength lubricating film are essential functions of a quality gear oil that need to be taken into account when choosing a product.


When is a gear oil change due?


f the vehicle manufacturer or transmission manufacturer stipulates a replacement interval, this is the latest point at which the gear oil must be changed. If manufacturers do not provide a service interval for gear oil, then it is often left to the discretion of the vehicle owner or garage to suggest an oil service.


Prevention is better – and cheaper – than cure, so replacing the gear oil in good time not only works out cheaper in the long run, it also gives you peace of mind.


Once the gear oil has started to break down, common symptoms start to surface, such as

  • gear selection problems
  • noise from the gearbox and final drive
  • judder


which, if left unchecked, will result in internal damage and component failure.


The oil must be changed at the very latest, when problems caused by inferior quality or degraded oil manifest themselves. The first warning signs that gear oil is breaking down, is when gear selection at low ambient temperatures starts to suffer. Whine and abnormal noise coming from the transmission system are another indicator that you need to take action because the oil is obviously degraded and the time has come to replace it.


Aggravating factors, such as condensation forming inside the casing, can put the gear oil under additional stress. Gear oils must be able to absorb a certain amount of moisture or condensation in a similar way to brake fluid. If, however, gear oil can no longer absorb condensation, the result is a breakdown of corrosion protection and the formation of rust inside the unit. Damage due to deposits forming or contamination of the oil is then only a matter of time.


Why is BIZOL Gear Oil the right choice for you?


Put simply, we put in the long hours. BIZOL has done its homework, but we also listen intensely to feedback from the market. We pride ourselves on the quality of our products, striving to deliver quality to our customers day-in, day-out. As it happens, quality can be measured, which is why BIZOL is also certified by the European Engine Lubricants Quality Management System.


All BIZOL MTF oils offer outstanding levels of protection against oxidation and thermal stress, stable extreme-pressure lubrication protection even at high temperatures, whilst offering exceptional wear protection and great fuel-saving potential.


BIZOL Allround TDL 75W-90 is multi-grade gear oil for manual gearboxes and hypoid gear final drives.


Allround TDL 75W-90 is a Total DriveLine gear oil that covers a wide range of passenger car and commercial vehicle applications and meets the specifications of API GL-4. It simplifies the range for consumers and reduces the amount of stock garages need to carry.


It offers optimum lubricating properties, high wear protection and can be used for long service intervals. Highly stable EP additives ensure a strong and reliable lubricating film even under extreme loading. The smooth-running characteristics of this gear oil also have a positive effect on fuel consumption.


The main benefits of Allround TDL 75W-90 include:


  • effective at low temperatures
  • effective wear reduction
  • meets the requirements of modern commercial vehicles


BIZOL Allround Gear Oil MTF 75W is blended for manual transmissions.


Allround Gear Oil MTF 75W uses the latest additive technology and is compatible with a wide range of materials in gearboxes and meets the specifications of API GL-4. BIZOL Allround Gear Oil MTF 75W was especially developed for manual gearboxes and double clutch gearboxes (S tronic and DSG). It offers the highest levels of fuel saving potential as well as excellent shear stability and optimum wear protection.


The main benefits of Allround MTF 75W include:


  • pressure-stable lubrication protection even at hot temperatures
  • excellent protection against oxidation and thermal stress
  • excellent wear protection with high fuel-saving potential


To see the full range of gear oils we offer, please consult our website: https://www.bizol.com/products/full-product-range/gear-oil/

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