Automatic Transmission Fluid (ATF) is a lubricant primarily used to reduce friction between moving parts. 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.
ATF also acts as a coolant in an automatic gearbox, and through general usage it becomes less effective. Once degredation occurs it becomes more difficult to dissipate the heat produced from moving parts. It also loses its lubricating properties, therefore accelerating wear between the rotating surfaces which can cause total failure if not rectified.
When to Change Gearbox Oil?
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 refresh regardless, as a lifetime is regarded as 100,000 miles despite many vehicles lasting much longer than this.
In all areas of a car with moving parts, metal shavings can also contaminate the oil which is then making contact with the rest of your internals – and isn’t very good at lubricating the moving surfaces.
It’s important to check the service schedule of your particular vehicle, as it may differ from the advice given. This can be completed yourself, which will prolong the life of your gearbox and be cheaper than replacing it when it fails!
How Often Should you Change Transmission Fluid?
Your driving style will dictate the ideal interval. For example if you drive mainly motorway miles you can wait until your manufacturer recommends a service. Generally 60,000 for an automatic gearbox and 100,000 for a manual. This will differ greatly depending on your vehicle and manufacturers service intervals – be sure to check specific to your vehicle!
On the other hand if you drive in a lot of stop start traffic, tow, plow snow or live in a hot climate, it would be wise to swap fluids earlier for maximum life. In these applications the fluids temperature is much higher than normal increasing degredation and wear. As a simple reminder you can remove old ATF twice as often as your manufacturer recommends.
How much does it cost to Change Gearbox Oil?
You can expect to pay between $100 and $250 depending on vehicle, labour prices in your area and quantity of ATF 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 rebuilt transmission, it’s not a huge cost and is relatively easy to complete yourself – it’s worth noting to remove the fill plug before the drain plug!
Sealed Gearbox Oil 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 gearbox 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 pump to suck/fill via the drain/fill holes. By being sealed it means no contaminants can mix with the oil, the downside is maintenance is much more difficult. As it’s sealed this makes it slightly more time consuming, expect to pay between $100 and $300 all in.
Transmission Fluid Change vs Flush
There is a slight difference between a change and flush. When you remove the drain plug, you rely on gravity drawing out the old ATF through the drain hole. This can leave over 50% of the old ATF trapped in crevices that are unable to drain through gravity alone. Once you introduce the new oil, old and new oil will mix – although this is better than doing nothing, a flush can completely clear all internals of contaminants.
A flush is where new ATF is pumped around the internals, pushing all of the old fluid out of the areas where it’s trapped from draining normally, for example the torque converter. This means virtually all of the fluid is new, resulting in a better lubrication and heat dissapation which extends the life of your transmission, and removes metal shavings which occur through normal wear and tear.