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Understanding the Difference Between Engine Oil and Transmission Fluid

Mechanic checking engine oil

Engine oil and transmission fluid are two essential yet vastly different fluids for your vehicle. A surprising number of people damage their cars by substituting one of these fluids for the other. Understanding these fluids and how they work can help you better care for your vehicle.

Engine Oil

Engine oil is formulated to protect the parts inside an internal combustion engine. Oil lubricates the critical components and eliminates high friction between the moving parts. Oil protects the engine from rust and corrosion and keeps the machine sludge-free.

Engine oil is generally amber in colour and turns black over time. Signs it’s time for an oil change include:

  • The change oil light is on
  • Oil levels are low
  • Oil appears black and dirty
  • The engine is knocking
  • Smoke is coming from the exhaust

You need to change the oil in your car approximately every 5,000 – 8,000 kilometres.

Transmission Fluid

Unlike engine oil, transmission fluid acts as a hydraulic fluid and helps your gears change smoothly and effortlessly. Transmission fluid protects the gears and clutches from friction. It has a higher viscosity than engine oil.

Automatic transmission fluid (ATF) is typically a deep red. However, manual transmission fluid is usually dark green. ATF operates in a closed system and doesn’t go through the rigours of engine oil. Therefore, you don’t have to change it nearly as often as oil; every 80,000 to 100,000  kilometres is recommended. Manual transmission oil should be changed a little more frequently, every 50,000 to 80,000 kilometres.

If you have low transmission fluid levels, it may be due to a leak. Look for a puddle of red or green liquid under your car. Other signs that you need to change your transmission fluid include:

  • Shaking or jerking motions
  • Check-engine light is on
  • Burning or sweet odours from overheated transmission fluid
  • Delay or hesitation when you change gears
  • Noises when the car is in neutral
  • The car seems to shift gears or change to neutral by itself

Never drive with low transmission fluid levels, as it can severely damage or ruin your transmission, resulting in a costly auto repair. Moreover, never put engine oil in your car’s transmission or transmission fluid in your car’s engine.

Oil Change and Auto Repair in British Columbia and Alberta

At Minit-Tune & Brake Auto Centres, we provide oil change services, transmission fluid replacement and transmission and engine repair services. We have 15 convenient locations throughout British Columbia and Alberta. Download one of our online coupons for a discount on your next oil change. Contact us today to book your appointment.


Minit-Tune & Brake Auto Centres Address Common Issues

Here at Minit-Tune & Brake Auto Centres in British Columbia, we’re always pleased to help our customers get the most out of their cars and trucks. To that end, we’ll add a relevant blog topic from time to time to keep you up to date and getting the most out of your vehicle.