ATF is a lubricant primarily used to reduce friction between the moving parts within your transmission. It’s common for different colours such as red or green to be used, making it easy to distinguish it from other fluids used in your vehicle.
It also acts as a coolant, however, once the fluid starts to break down with age/usage it becomes more difficult to dissipate the heat produced. It also loses its lubricating properties, therefore accelerating wear between the rotating surfaces which can cause total failure if not rectified.
How Often to Change Transmission Fluid?
As a general rule fluids should be changed on or before 100k miles. Some manufacturers claim these are “lifetime fluids” however it is advised to regardless. The oil cannot retain its lubricating and cooling properties for the lifetime of a vehicle, as they degrade with age and usage.
In all areas of a car with moving parts, metal shavings can also contaminate the oil which is impeding your oils ability to lubricate.
It’s important to check the service schedule of your particular vehicle, as it may differ from the advice given. It's generally easy to perform yourself, which will prolong the operating life of your transmission and be cheaper than replacing it when it fails. Grinding when changing gears or slippage can be eliminated by performing the correct maintenance according to your service schedule too!
Your driving style will dictate the ideal interval. For example, if you drive mainly motorway miles you can wait until your meet your manufacturer interval. Generally 60,000 for an automatic gearbox and 100,000 for a manual is recommended - this is only a generalization, your vehicle service schedule may differ.
On the other hand if you drive in a lot of stop-start traffic, tow, or live in a hot climate, it would be wise to reduce your service interval for maximum life. In these applications, the temperature is much higher than normal increasing degradation and wear. You could half the mileage that your manufacturer recommends to keep it simple.
How much does it cost to change transmission fluid?
You can expect to pay between $100 and $250 depending on the vehicle, labour prices in your area and quantity of oil needed. A dealership will be on the upper end of the scale, generally costing 3x as much as an independent garage!
If you decide to do this yourself, you can expect to pay between $10 and $20 per quart, as well as the price of drain/fill plugs if these are recommended to be changed.
Considering the price of a rebuild, it’s not a huge cost by comparison, and is relatively easy to complete yourself – it’s worth noting to remove the fill plug before the drain plug!
Sealed Transmission Fluid Change Cost
Manufacturers have started to make maintenance more difficult to DIY, increasing their profits and keeping customers purchasing newer vehicles. Designs such as a sealed transmissions ensure they last long enough for your warranty to expire before potentially costing big money.
In order to drain or fill, you have to use a siphon pump due to the location of the fill plug. By being sealed it means no contaminants can mix with the oil, the downside is maintenance is much more difficult. As a sealed transmission is slightly more time consuming, expect to pay between $100 and $300.
Fluid Change vs Flush
When you drain fluid, you rely on gravity drawing out the old oil through the drain plug. This can leave over 50% of the old oil trapped in crevices that are unable to drain through gravity alone. Once you refill the transmission older fluid and new will mix – although this is better than no maintenance at all, a flush can completely clear degraded oil.
A flush is where the old oil is drained and new fluid is pumped around the transmission, pushing all of the old lubricant out of the areas where it's trapped from draining normally. This means after a flush there is no residue and old oil, resulting in better lubrication and heat dissapation, and removes metal shavings which occur through normal wear and tear.