Gearbox Flushing Most Common FAQs Answered | CCM Blog

Gearbox Flushing Most Common FAQs

Our gearbox flush service is becoming more and more popular so we thought it would be worthwhile sharing why this process is so important. Gearboxes are complex, and we don’t expect our customers to understand every element of them. What we do want to do is share our knowledge to educate drivers about their vehicles, allowing them to make informed decisions about the services they need.

Let’s start from the very beginning…

What Is Gearbox Flushing?

Simply put, gearbox flushing is a process to get all the gunk and dirty oil out of your gearbox. It differs from a basic gearbox service as we make sure to remove all the contaminated oil. We also replace the filters and include additives to make your oil stay clean for longer.

Why Do I Need a Gearbox Flush?

Oil naturally degrades over time and particles from the usual wear and tear get into the oil ways. This causes the gearbox to struggle to push the oil through the system with the filters becoming sludgy and clogged. A gearbox flush allows your gearbox to work smoothly and happily.

You may be experiencing some issues with your gearbox such as shocks or judders, over-revving or increased oil consumption. These can be tell-tale signs of your gearbox screaming for a service.

Gearbox Flushing on an Audi In Process at CCM Ewhurst

When Do I Need a Gearbox Flush?

Much like the standard engine oil and filter change that we recommend you have each year, we also recommend a gearbox flush, but not nearly as often. Each manufacturer will recommend slightly different intervals but as a good rule of thumb, we recommend between 60-70,000 miles or every 5 – 6 years. If you are unsure if or when yours is due, give our team a call with your registration and current mileage and we can advise you.

What Happens in a Gearbox Flush?

Because we have some of the best tools on the market, we are able to withdraw the old oil from your car whilst running the gearbox in gear (forward flushing). We add an additive that turns the current oil into a cleaning solution so it can help to break down existing contamination within the unit. We pull out this dirty oil and fit the new gearbox filters. Then we add in slightly too much oil to ensure the pipes are clear before draining off the excess. At the end of a gearbox oil service, we will use the service machine to pump in an additive called an Automatic Transmission Treatment. This product is an oil-soluble supplement designed to stop and prevent leaks and to ease and smooth gear change and selection.

Close Up of a Gearbox Flushing at CCM Ewhurst

What Are the Symptoms of Needing a Gearbox Flush?

There are a few common symptoms to look out for these include:

  • Slipping gears and over-revving – caused by internal pollution combined with wear
  • Fluctuating RPM – caused by fluctuating oil pressure because of the inconsistency of ATF fluid
  • Shocks or juddering during gear changes – caused by internal pollution and oil degradation. The switching valves in your gearbox can’t react fast enough
  • Correct gear not being retained – clogged oil passages cause weak insufficient oil pressure to maintain gear selection
  • Kick-down not working properly – sluggish kick-down is usually caused by switching valves getting polluted and the clogging of oil ways reducing oil flow
  • Increased oil consumption – all of the above can lead to increased oil consumption as the gearbox functions are restricted and the drive train is hampered

What Tools Do We Use for Gearbox Flushing?

We are regularly investing in new tools and equipment and our gearbox oil flushing machine cost us over £5000 as we wanted to make sure we got the best piece of kit on the market. We have partnered with Wynns Automotive as our supplier for our automatic gearbox flush treatments and additives. Wynn’s has been the global leader in additive technologies since 1939 so we know we can count on them. These are chemical treatments that improve the way your gearbox oil works. Adding these treatments to the oil flush helps to break down nasty contamination before removing the old oil. At the end of the service, we use the machine to pump in the Automatic Transmission Treatment. This is an oil-soluble supplement designed to stop and prevent leaks and to ease and smooth gear changes.

Gearbox Flushing on an Audi In Process at CCM Ewhurst

Why Choose CCM for Gearbox Flushing?

We often speak to customers who believe they can get the same service elsewhere for less. But we would advise you to approach with caution. Many garages will only drain the old oil from the gearbox and then top it up with fresh oil. This isn’t the same as a flush! A gearbox flush removes 99.9% of oil and containments, an oil replacement only removes about 60%. This is because other garages simply open the drain plug in the base of the gearbox, leaving around 40% of the oil stuck within your torque converter and around the gearbox. As you can probably tell, this isn’t nearly as efficient as a flushing service.

If you are bringing your car to us for a gearbox flush because of issues you have noticed with performance, it’s also worthwhile for us to do some initial diagnostics first to make sure this is the best course of action for you.  Our aim is to get your vehicle back to you as soon as possible with all issues resolved. You can learn even more about gearbox flushing here!

Professional gearbox service

Keep your gearbox happy and healthy

Leave a Reply