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Gearbox Oil: Synthetic or Conventional?

Choosing the right gearbox oil is essential for maintaining your vehicle’s transmission. Both synthetic and conventional oils have their benefits and drawbacks that can often depend on your needs, the vehicle that you drive and the performance you expect from your vehicle. While every manufacturer will have their recommended oil type, if you are unsure of which is best for your vehicle, we are here to help. Here, we’re taking a detailed look at both types, as well as their pros and cons, to help you make an informed decision.

Synthetic Gearbox Oil

Synthetic oils are carefully created and manufactured through a series of chemical reactions and different pressures and temperatures. This process creates a product that is resistant to breakdown, uniform in molecular sizing and weight and ultimately, less vulnerable to oxidation over time. This can all work to ensure the oil is less likely to change consistency in different temperatures, whether thickening in the cold or thinning out in the heat and offers a more predictable drive. However, there are some drawbacks too, including higher cost, and the fact that some older vehicles may not be compatible: 

The Pros:

  • Superior Performance: Synthetic oils are engineered to perform better under extreme temperatures and high-stress conditions, providing superior lubrication and overall more trustworthy performance compared to it’s conventional counterpart.
  • Longevity: Due to the way they are produced and their resistant and stable qualities, synthetic oils tend to last longer, reducing the frequency of oil changes.
  • Improved Efficiency: Synthetic oils reduce friction more effectively, which can lead to better fuel efficiency and smoother gear shifts.

The Cons:

  • Cost: Generally speaking, synthetic oils can often be more expensive than conventional oils.
  • Compatibility: Some older vehicles may not be compatible with synthetic oils, so this can require careful consideration before switching. If you are unsure, check your manufacturer’s handbook or get in touch with our team for support.

Conventional Gearbox Oil

Conventional oils, also referred to as mineral oils, are the ‘natural’ form of oil that cars have used for decades. This refined form of crude oil is typically extracted from the ground, and then processed to refine the substance into an oil safe to use in our vehicles. It is generally more cost-effective for those on a budget and is deemed to be perfectly fine for standard or casual use, however the different molecule sizes can lead to more rapid oxidation, a higher chance of changing viscosity in different temperatures and a shorter lifespan:

The Pros:

  • Cost-Effective: Conventional oils are generally cheaper than synthetic oils, making them more affordable for regular maintenance.
  • Adequate for Standard Use: For everyday driving and moderate conditions, conventional oils can provide adequate protection and performance without concern for breakdown or build-up. 

The Cons:

  • Shorter Lifespan: Due to their molecular structure, conventional oils break down faster than their synthetic counterparts, which may mean more frequent changes.
  • Less Protection: They may not perform as well under extreme temperatures or quickly changing temperatures, as well as heavy loads or unique driving conditions, leading to increased wear and tear over time.

Making the Right Choice

Generally speaking, your manufacturer will often provide a recommendation for your vehicle on which oil is best. It is best to follow these recommendations, however if you have the choice, knowing which is best could save you time, money and stress. When deciding between synthetic and conventional gearbox oil, consider the following factors:

  • Driving Conditions: If you frequently drive in extreme or rapidly changing temperatures or engage in high-stress driving (towing, off-roading), synthetic oil may be the better option.
  • Vehicle Age and Compatibility: Check your vehicle’s manual or consult with your mechanic to ensure compatibility with synthetic oils, especially for older models. Newer models may also recommend synthetic oil in order to ensure performance.
  • Budget: If you are on a stricter budget, you should also take this into consideration. However, while synthetic oils are initially more expensive, their longer lifespan can offset the cost over time.

Both synthetic and conventional gearbox oils have their advantages and disadvantages. Understanding your vehicle’s needs and your driving habits will help you choose the right oil for optimal gearbox performance. For personalised advice and regular maintenance, we are on hand to help. Simply get in touch with a member of our team here at Service4Service for gearbox repairs or maintenance queries, today.