Transmission issues are one of the many things that a car owner dread. It takes a long time for an engine demonstrating signs of problems to fail catastrophically, but it doesn’t take long for a seemingly minor shift issue to completely cripple a car and leave you stranded.
Along with the increasingly complex architecture of modern transmissions, transmission reliability is now a top concern for many new car owners. That said, transmission-related problems weren’t always such a major point of consideration for car buyers.
Back a few decades when manual transmissions were prevalent, they were the go-to choice for many as the choice for work vehicles. Even automatic transmissions back then were mostly brake-band units that were enduring, to say the least. These transmissions would last thousands of miles mostly trouble-free.
- Purpose of Transmission Fluid
- Signs of Poor Transmission Fluid
- Transmission Fluid Change Costs
- DIY Process
- Change VS Flushing
Maybe your automatic transmission would develop slight jerks upon shifting, but nothing especially concerning. Everything was purely mechanical so there wasn’t much that can go wrong. Nowadays though, automatic transmissions are built up of countless intricate electrical parts, something going wrong can end up with you left stranded.
Therefore, it is important that you recognise the signs of a transmission related issue and consult a workshop when possible. However, before that, there is something that many workshops will recommend you to carry out first – replacing your transmission fluid.
Purpose of Transmission Fluid
Arguably, within an automatic transmission, the single most important thing is the transmission fluid. Imagine it as the blood flowing through our body. Without transmission fluid, or if there’s too much of it, your transmission won’t be able to function normally.
The purpose of the transmission fluid is simple, it’s used as a medium to transfer hydraulic pressure from one end to another. The transmission control unit controls the flow of the transmission fluid using the valve body and the transmission solenoids. A mechanically driven transmission oil pump keeps the oil constantly pressurised.
By changing how the solenoids are activated, the flow of the fluid within the valve body alters to pressurise different sets of clutch packs. With this, different gear sets can be engaged to shift into different gears.
Therefore, from the operation of a gearbox, it can be observed that the condition of a transmission fluid must be optimal for shifts to be carried out smoothly. However, with the design of an automatic transmission, the fluid itself doesn’t need to be changed too often in normal circumstances.
Why is routine transmission fluid change often neglected
You might think to yourself that no one has really reminded you that the transmission fluid in your car needs changing anytime soon. This is because modern automatic transmission fluid can actually last quite a long time, with design features incorporated within an automatic transmission to prolong the fluid change time.
First of all, there’s an automatic transmission filter within the system. When properly done, this filter should be replaced every time you change out the transmission fluid. Furthermore, an automatic transmission is an enclosed, recirculating system. This means that no foreign dirt particles should be introduced within the fluid.
Therefore, under normal operation, the fluid level shouldn’t change. This means that no topping off is necessary. Most automatic transmissions also implement a fluid cooler to prevent overheating under heavy load. This helps to prevent overheating, which is especially prevalent in offroad vehicles with automatic transmissions.
The other major factor is a bit of a blunder in the automotive industry. A decade or so ago, some manufacturers decided to market their transmission as ‘maintenance-free’. These automatic transmissions were supposedly included with ‘lifetime transmission fluid’.
Needless to say, to anyone who understands how transmission fluids function, it’s impossible for a transmission to be maintenance-free. Transmission fluids go through dozens of heat cycles that eventually breaks down the constituency which contributes to fluid degradation.
And once the transmission fluid degrades, it stops being efficient at pressurising and sustaining optimum capability at high temperature. Thus, for the owners that did not replace their transmission fluid experienced premature transmission failures early on into the ownership.
The other big factor for some is the cost to replace automatic transmission fluid. Depending on the vehicle model, transmission fluid changes can cost upwards of ~ $200. Often, the schedule also coincides with a major service, so some owners will opt to stretch the fluid change mileage. This is ill-advised, as ignored fluid changes can contribute to bigger problems later on.
Signs of Poor/Low Transmission Fluid
Once you have a better understanding of how transmission fluid works and why it needs to be changed regularly, you might question whether if your transmission is displaying signs that it needs a fluid change.
Poor shift quality
A major sign that you need a fluid change is when you start to notice increasingly worse shift quality. First, the transmission might only jerk a bit during upshifts, but it will develop further into rough shifts that buckle the entire car.
In cases where it gets really bad, your transmission might even start slipping in and out of gears. You’ll notice that the car refuses to change gear because the transmission fluid pressure is inadequate. It’s possible that this happens under load, or even when cruising.
If your transmission starts to slip, it will trigger an automatic transmission fault code. In some cars, this will force the transmission into ‘default’ mode, or limp-home mode. In this case, your transmission will be locked into a single gear and a warning light will appear in your instrument cluster.
Dirty transmission fluid
It’s obvious, but if you have a transmission fluid dipstick, you can always just pull it up to inspect the fluid condition. Using a paper towel, acquire a sample blotch of the fluid. Look for images of worn transmission fluids online. There should be images that you can compare your fluid colour to.
In general, if your transmission fluid is a bright colour (typically pink, red, blue or gold), then you’re in good shape. This means that it has just been changed out recently, and it’s in good condition.
However, if it’s murky and dirty, then it’s due for a change. Typically worn transmission fluids darken in colour from the heat. If it’s milky in colour, this means that coolant has contaminated the transmission fluid and the leak must be rectified as soon as possible.
In some cases, the transmission fluid might be a burnt, almost black colour. This means that the transmission fluid has overheated and it must be replaced as soon as possible. Internal damage might have occurred as well in the form of a burnt clutch pack. This can happen due to excessive slippage or just degradation in fluid quality.
How Much Does Transmission Fluid Change Cost
Of course, owners are sometimes apprehensive to transmission fluid changes due to the higher cost associated with it. You might hope to delay the transmission fluid change interval, but it’s not worth it in the long term. Late fluid changes cause unnecessary wear to the internals of an automatic transmission.
It’s a common mistake for consumers to compare the costs of an oil change to a transmission fluid change and determine they’re being swindled by a dishonest workshop. However, transmission fluid changes are usually more expensive, due to the greater fluid cost and higher labour.
A major contributor to the steep maintenance cost is the fluid used. Depending on the transmission your car is using, you’ll need different transmission fluid that varies wildly in price. And unlike oil changes, it’s not recommended to mix transmission fluids of different manufacturers and standards together. If you’re using Toyota T-IV ATF, you should stick to the T-IV on subsequent changes.
You’re expected to spend around $10 per quart of transmission fluid. How much you need is highly dependent on your transmission type. If you have a normal 4-speed transverse, you might only need about 2.5 to 3 qt of transmission fluid. However, if you have a modern 9 or 10-speed longitudinal automatic, you might need upwards of 7 to 8 qt per fluid change.
It’s also advised to replace your transmission filter while changing the fluid, along with the transmission pan seal. The cost for them ranges from $20 to $50 depending on your car model. However, on newer cars, especially luxury cars, it gets complicated.
The transmission fluid pan can be made of plastic, with the fluid filter element built right into the pan itself. This means that the pan needs to be changed together with the filter. Costs of the filter for these cars skyrocket because of this. You can expect to spend over $300 for the filter alone.
Adding labour costs, which is typically around $80 for an independent shop, total cost sums up to around $150 to $250 per transmission fluid change. That said, if you have a luxury car that requires 10-litres of transmission fluid and a transmission fluid pan, it can be over $700 for a fluid change.
When Should I Replace the Transmission Fluid
While transmission fluid changes costs a lot more than oil changes, you only need infrequent fluid changes to keep your transmission happy. Generally, it’s recommended that you get your transmission fluid changed ever 30,000 miles to be safe. That’s approximately every 3rd or 4th oil change.
That said, some manufacturers are claiming that their transmission fluid lasts longer, and only requires inspection every now and then. Fully synthetic transmission fluids such as Toyota WS ATF can last as long as 120,000 miles. GM claims their 10-speed transmission fluid Dexron-ULV can endure 150,000 miles.
Those are assertions from manufacturers only, of course. The extended fluid change intervals appeal to the everyday consumer. To better get an idea, browse through the owners’ forum for your particular vehicle model. Other owners should chime in and provide a conservative gauge on when to replace your transmission fluid.
With that said, if you’re gentle on your car and powertrain, then you should be able to make do with 60,000-mile fluid changes. Gentle meaning that you rarely put high load through your transmission. Therefore, this applies if you don’t tow or don’t perform spirited drives often. Going off-road also puts an immense load on your transmission and differential.
What About Other Transmissions and Costs?
Dual-clutch transmissions (DCT) Fluid Change Costs
Most of automatic transmission maintenance guidelines apply to dual-clutch transmissions as well. Dual-clutch transmissions are more akin to manual transmissions with only two clutch packs. However, if you’re behind on maintenance, the clutch packs can fail catastrophically relatively quickly. It’ll also cause shifting issues throughout all gears.
That said, ensure that you’re using transmission fluid designed for DCT purpose. DCT fluids are generally more expensive though. These fluids are formulated to handle extreme pressures with anti-wear additives for the constant mesh gears.
DCT fluids and filter should be replaced every 40,000 miles to be on the safer side. You definitely don’t want to skimp on maintenance for DCT equipped vehicles. This means to use parts that are up for the job. Typically, DCT routine maintenance can cost somewhere between $300 to $700 depending on your car model.
Continuously-variable Transmissions (CVT) Fluid Change Costs
CVTs have generally had a negative perception. Using a steel belt generally meant that it’s not as durable and early on some manufacturers claimed that CVTs don’t need maintenance at all. This is of course false once again, as metal shavings can contaminate the fluid and reduce its friction properties.
Nowadays though, CVTs can actually endure the test of time if taken care of. Again, the maintenance schedule is very similar to automatic transmissions. For CVTs to last long you’ll want to replace the fluid every 30,000 miles for normal to heavy usage, and 60,000 miles for gentle applications.
While ATF can be used for CVT transmission if needed, it’s definitely not recommended. CVTs are constructed very differently to conventional automatic transmissions. It runs by turning a flexible output pulley with a steel belt. CVT fluids have friction modifiers to reduce slippage on the belt itself. ATFs actually have friction-reducing modifiers to prolong transmission life instead.
CVT fluid changes can be a bit more expensive due to the unique fluid it uses, but it generally needs less fluid. Expect to spend around $200 to $300 for a CVT fluid change depending on the workshop you consult.
Manual Transmissions Fluid Change Costs
Manual transmissions are favoured by many for the involved experience and generally more robust for a means of delivering power to the wheels. Prior to the vast improvements developed in automatic transmissions, manual transmissions are preferred. With that said, the maintenance schedule remains similar to other transmissions.
Unlike the aforementioned transmissions, manual transmissions fluids are used primarily to lubricate the constant mesh gears within the transmission. Shifting is taken place by operating the shift lever which mechanically pushes shift collars that connects the input shaft to the output shaft. The clutch is dry and operated by the driver.
You’re recommended to replace manual transmission fluid every 30,000 miles for most vehicles. For heavy usage, the interval should be shortened to every 15,000 miles. Manual transmission fluid can range from $5 per qt to $20 per qt due to varying properties. They also often have no filters that need changing. That is generally achieved by a magnetic drain nut that traps metal shavings in the fluid.
DIY Transmission Fluid Change Keeps the Price Down
The great thing about routine maintenance items is that manufacturers generally design them to be easy to work on. This applies to every type of transmission your car might have. In most cases, replacing the transmission fluid is no more complicated than an oil change. That said, removing the fluid pan and replacing the filter can be time-consuming.
Depending on where you live, the high repair cost can be attributed to high labour costs. Therefore, performing a DIY fluid change can save you the labour cost. With a bit of mechanical aptitude, it should be a straightforward job.
Tools Needed For Transmission Fluid Change
Before you commit yourself to the fluid change though, you’re going to need basic hand tools. A socket set can speed up the process considerably. Floor jacks and jack stands are also necessary so you can access the transmission fluid pan. For some cars, you might need to purchase the transmission dipstick separately as a special tool.
You should also consider purchasing a drain pan that makes it easy to drain and contain used oil for disposal. In most cars, you can just refill the transmission fluid from the dipstick tube with a basic funnel. The tube might be low, so a funnel with a long flexible neck can be invaluable. A creeper or just some cardboard boxes to lay on would be worthwhile too.
Some cars that don’t have a dipstick tube requires the use of a transmission fluid hand pump though. You’ll also need a diagnostics scanner to determine the fluid level afterwards. Other than that, you’re going to need the recommended transmission fluid for your car and the transmission service kit. The kit should include the filter and fluid pan seal.
Transmission Fluid Change Steps to Take
Search online for the transmission fluid specifications of your car. If applicable, look for documentation regarding the procedure of replacing the transmission fluid for your car. It will ease the process considerably knowing what you’re getting yourself into.
First, you’ll need to jack up your car. Look for proper jacking points on your car and make sure the ground surface is relatively flat. The owner’s manual should contain information on jacking your car. Locate the jacks stands somewhere sturdy. Before getting underneath your car, give it a good shove to make sure it won’t slip off the stands.
To ensure that you have a clean drain, you might want to start your car and row through the gears. You would want the transmission fluid to be warm, but not uncomfortably hot. It’ll also speed up the draining process. Shut off the engine and crawl underneath your car. The drain nut should be on the bottom of the transmission, or on the fluid pan itself. Be wary of the hot exhausts around the transmission.
Ready the drain pan and remove the drain nut. Allow the fluid to drain itself for approximately 5 minutes. When it’s nearly empty, plug the drain nut back in. The next step is to remove the fluid pan. In most cars, this should be quite straightforward. In some rear-wheel-drive cars though, you might need to remove the transmission cross-member for access.
Before removing the pan, you should keep the drain pan underneath. There will be residual transmission fluid in the fluid pan and also transmission fluid will continuously drip from the transmission. It’s going to be quite messy unless you’re extremely cautious.
A complete fluid change also encompasses replacing the fluid in the torque converter. There’s usually a plug covering the torque converter. You might need to turn the engine over by hand to reveal the drain plug for the torque converter.
With the transmission fluid pan out of the way, you should be able to replace the filter easily. Some can be removed by just pulling it, others might be bolted in. Don’t just yank it out immediately. Also, replace the transmission fluid pan seal and clean the sealing surfaces. Reinstall the transmission fluid pan, taking care not to over-torque the bolts.
Refilling the Transmission With Fluid
It helps to know the amount of transmission fluid needed for your transmission beforehand. To be on the safe side, fill in less than the specifications first. This might be done from either the fill hole or the dipstick tube depending on your car. Afterwards, lower the car and start the engine. Take the car out for a drive to get it to operating temperature.
Park the car on a level surface and shift into neutral gear. Pull out the transmission dipstick, wipe off the transmission fluid, insert it and pull it out again. Check whether if the fluid is between the indicated maximum and minimum. Some dipsticks have a hot and cold indicator as well. Cars without a dipstick may require you to drain off the excess fluid from the drain hole.
Transmission Fluid Change VS Flushing
Sometimes, your mechanic might recommend you to perform a transmission flush. This is basically replacing the entire transmission’s worth of fluid with new fluid. Sometimes this is necessary because while you can drain the transmission fluid, you can’t do a complete drain. There will still be old fluid leftover in the valve body and within the transmission itself.
There are machines that are purpose-built for forcing new fluid through the transmission. However, DIY flushing can be done by draining, filling, running the transmission and repeating the steps for 2 or 3 times. You can also remove the fluid return line and allow the old fluid to bleed out from the transmission.
Flushing becomes necessary when there are signs that your transmission fluid is contaminated or overheated. Contaminated meaning if it’s too dirty or has coolant mixed in. Of course, if coolant is mixed with the fluid, a leak has definitely developed that needs rectifying before flushing out the contaminated fluid.
That said, if inspecting your fluid shows sign of contamination or overheating, then there’s a good chance that internal damage has occurred. Flushing is a temporary remedy at best. If you take proper care of your transmission, a transmission fluid flush shouldn’t be needed at all.
Normally when conducting a transmission flush, you would need about 1 or 2 quarts of extra transmission fluid. The labor costs are higher, but some workshops or dealers offer transmission flushes at the same rate. Therefore, expect to pay about $50 to $100 more for a transmission flush.