How Often Should You Service Your Automatic Gearbox? MILTA Technology

How Often Should You Service Your Automatic Gearbox?

Regular servicing on your car in general is the key to keeping it in the best-possible condition. It’s for this reason that OEMs issue their individual maintenance schedules that use various odometer milestones as reminders for when you should get certain maintenance done on the car. As it happens, a lot of damage done to cars is a result of people thinking that they’ll save some money in the short term by skipping steps on that schedule. The real result is that they end up with more costly repairs being needed further down the road.

If you drive a car with an automatic transmission, then that component is also in need of proper maintenance and servicing, but when? You might rotate your tyres and change your oil once every 5,000 miles, but is the transmission in such regular need of attention? This is a point that we will try to clarify in today’s blog.

Background: The 15-month Rule

First and foremost, we should start by saying that car owners should follow their individual OEM-issued maintenance schedule for a more precise idea on when their engines need servicing, especially if the car is older. However, if for some reason you can’t find that, then here’s a good rule of thumb: you should get your automatic gearbox serviced about every 15 months, or 15,000 miles, whichever comes first.

The good news is that here in the UK we don’t experience climate extremes like some other parts of the world, so the general rule of thumb becomes quite accurate and doesn’t need to be modified to account for the extreme heat of somewhere like Phoenix, Arizona, for instance, nor the extraordinary cold of Manitoba, Canada. That should deliver a total lifespan of about 124,000 miles unless something else extraordinary happens to it such as your car being in an accident or if your driving style is uniquely aggressive and sloppy with the transmission.

What Happens During an Automatic Transmission Service?

Besides routine checks on the main components of your transmission: input shaft, torque converter, planetary gears, clutch pack, output shaft, bellhousing, etc, the main work of a typical automatic transmission service is to check on and change the transmission fluid. Now, while checking the fluid is important every 15 months, you almost certainly won’t need to change the transmission fluid that often.

Automatic transmission fluid can will typically be changed every 60,000 miles, but of course it depends on the condition of your fluid at the time you go in for a service. It doesn’t require as frequent a change as that of manual transmission cars.

When your transmission fluid is being replaced, technicians usually use a cleaning solution which is added to your automatic transmission before the unit is then run for 15 minutes. As it runs, the cleaning solution works to remove the buildup of various contaminants and sludge that gets in your transmission as a normal part of its operation. Once the cleaning is complete, the cleaning solution and old transmission fluid are flushed out and replaced with fresh fluid.

Why is Regular Servicing Important?

It’s very easy for people to think that their car is running fine and that therefore they don’t need to go in for the transmission service. Some people are prone to thinking that as long as the car is working, there’s no need to spend money on repairs and maintenance. They follow the old adage, “if it ain’t broke, don’t fix it.” The problem is, that’s not how automatic transmission units, or cars in general tend to work.

What starts as a minor fault in one of your transmission components, say the clutch pack, would be spotted and fixed up immediately during a regular service. To do that might cost you a little extra on top of your normal service costs, but it saves you from that clutch pack problem spiralling into a full-blown clutch breakdown, which could cost you more than £1,000 to get fixed up. Which bill seems the more worthwhile now?

That’s the trouble with cars, minor faults often don’t manifest into any noticeable issue with your car until it gets a lot more serious — and therefore a lot more complex and expensive to fix. The automatic transmission is one of the most intricate and complex components anywhere in your car. Most major repairs of the transmission will involve taking much of the transmission apart, which adds labour costs.

Benefits of Regular Servicing


Firstly and perhaps most obviously, whatever you spend on servicing the transmission in the shorter term will pay dividends in the long term when you avoid the huge repair bills faced by those who ignore key maintenance. Your transmission is a symphony of multiple moving parts. They have to be in perfect sync to work properly, and that means regular servicing is necessary. The financial benefits will become more apparent the more you get the job done.


The most important benefit is certainly safety. It is thoroughly unsafe to drive your car with an improperly maintained transmission. Even if you think the transmission is working fine, if it hasn’t been serviced then all kinds of things could be wrong with it, possibly resulting in a sudden transmission failure or breakdown. That could be very dangerous if you were driving at speed down the motorway when it happened.

Driving Dynamics

Finally, a well-serviced transmission is one that works better and delivers better driver dynamics! Gone are those pesky delays, the slippage and other problems that inevitably emerge when a transmission doesn’t get the attention that it needs. One particularly pesky problem with faulty transmissions is the lag time that can come. The time you put it into drive and press on the accelerator to the time the vehicle actually responds is what we’re referring to here, and if there’s a lag, it seriously detracts from the overall driving experience.

Therefore, we reiterate the benefit of following our recommendation on regular automatic gearbox servicing every 15 months or 15,000 miles.

One comment
  1. Hi, could you give me a price on a service on the gearbox of a BMW F25 2L LCI. It’s got 111704 miles on the clock. Cheers

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