The majority of people understand what engine oil is and why it has to be replaced on a regular basis, but transmission oil/fluid is often misunderstood or underappreciated. So, what is transmission oil? What is transmission fluid made of? We’ll explore the answer to these questions and more in this blog post.
Transmission oil is a lubricant designed to safeguard the vehicle’s clutch packs and gears while also allowing for crisp, smooth shifts. Without transmission oil, the vehicle’s gears will quickly overheat or wear out, leading to decreased transmission life and large repair bills. Transmission oil is just as necessary as engine oil.
Let’s start with the task that all lubricants accomplish.
The primary function of any oil is to form a fluid layer between components in order to avoid interaction and minimize friction. Lubricants guard against degradation and combat the harmful effects of excessive heat.
Transmission oil must…
- Be functional as a hydraulic oil
- Fulfill the required frictional criteria
- Effectively protect moving components and gears from wear
- Combat heat
The important features of lubricants consist of shear stability, viscosity, volatility, and low- and high-temperature performance. These useful features are common to all high-quality lubricants, but they can be customized to each application by using the right additives and base stock oils.
What exactly is a transmission?
Put simply, the transmission shifts energy from the motor to the wheels of the vehicle.
The transmission contains the solenoids, clutches, gears, and other pieces that determine which gear to use based on the operating circumstances. For instance, as you begin driving or tow a big workload, your vehicle shifts into a lower gear that offers additional torque. When you accelerate on the freeway, a higher gear is selected to decrease motor rpm and thereby improve power.
There are 2 kinds of transmissions: automatic and manual, and each has its own set of requirements for transmission oil. A manual transmission involves the operator engaging the clutch and shifting gears at the right times, while an automatic transmission shifts automatically as power and speed requirements adjust. Continuously variable transmissions (CVT) and dual-clutch transmissions (DCT) are two other transmission types.
It is important to understand the kind of transmission you have and the exact oil it takes in order to keep your vehicle operating properly. To find the correct transmission oil, check your owner’s manual or the AMSOIL product guide.
Automatic transmission fluid properties
A strong transmission oil not only cools and lubricates the transmission’s mechanical components, but it also shines with the following factors.
- Must be functional as a hydraulic fluid
To shift gears, automatic transmissions use transmission oil that is pressurized. This is a stressor that has the potential to shear the oil and lead to it losing viscosity.
- Must fulfill the required frictional criteria
For optimal results, the clutch packs have to engage and disengage perfectly.
- Effectively protect moving components and gears from wear
Automatic transmissions have a planet, sun, and ring gear mechanism that requires a long-lasting film of lubricant to deter metal-to-metal interaction.
- Combat heat
The heat generated by automatic transmissions is greater than that produced by manual transmissions. Heat hastens oxidation, which is the chemical degradation of the lubricant. Varnish and sludge are formed as a result of oxidation, and they can jam up slender oil pathways and lead to the glazing of clutches. In the absence of the proper safeguards, your vehicle can start to turn harshly, shake, or delay.
Manual transmission oil properties
Manual transmission oil is responsible for fewer tasks than automatic transmission fluid. Certain manual transmissions can use or even need to use ATF. However, there are certain characteristics that must be met by high-quality manual transmission fluids, such as shielding from corrosion soft metal (brass) synchronizers.
Transmission oil: Synthetic vs. Conventional
What is transmission fluid made of? There are two main types of transmission fluid: conventional and synthetic. Conventional transmission oil is derived from crude oil and the reorganizing of hydrocarbons to meet the requirements of various vehicles. Synthetic transmission oil is manmade within a laboratory through various chemical processes. During high operating temperatures, synthetic transmission fluid is less prone to degrade, thin out, or oxidize.
Is it necessary to change the transmission oil?
Absolutely. Transmission oil oxidizes and becomes filled with sludge and debris over time. Although transmission oil does not need to be replaced as often as engine oil, it should be checked on a regular basis.
You will find that your vehicle will shift poorly if the transmission oil level is low or the fluid has begun to degrade. Running low on transmission fluid can destroy transmission parts, resulting in major failure and/or costly repairs.
How frequently should I replace the transmission fluid in my vehicle?
The correct answer is dependent on the specific kind of transmission in your vehicle and the operational pressures that it is subjected to. Transmission fluid should be changed every 30,000-150,000 miles (48,000-240,000 km), according to industry standards. Always make sure to check the recommended range for your vehicle.
What about “filled-for-life” transmissions?
Wait a minute. The term “filled-for-life” transmissions is misleading.
There is no lubricant that can last indefinitely and offer the defense your vehicle and wallet deserve. Lubricants degrade over time, particularly when subjected to heavy pressures, repeated stops and starts, or regular short rides.
How often should I inspect my transmission oil?
It’s a smart idea to inspect the vehicle’s transmission oil condition and level around once a month or so. This job, however, is now more complex in new automobiles, which often don’t have transmission dipsticks or have them in difficult-to-reach positions under the engine. If your transmission performance is lacking, check your transmission oil as soon as possible.
How can I determine if my transmission oil is low?
The most common cause of transmission oil loss is transmission overheating. Transmission overheating is usually caused by low fluid or drained fluid as a result of a lack of daily fluid servicing.
If you have leakage in your transmission system, you can lose transmission oil and ultimately drive with low transmission oil levels. The transmission will start to experience overheating and sliding, and although this will not usually lead to the vehicle stalling, it will generally lead to the engine to revving faster than usual or giving the impression that there is no power.
When the oil levels are down, it can cause irreversible damage to your transmission and necessitate expensive rebuilds, replacements, or repairs.
Look for indications of leaks on the ground around the area you park, and if your vehicle happens to have a dipstick, inspect the transmission oil levels any time you switch out your oil. If it is even marginally depleted, you most likely have some minor leakage that will develop into a more serious leak and necessitate costly fixes in the future if the issue is not addressed promptly.
Depleted transmission oil symptoms
So, how do you know if your transmission oil is depleted? Here are several warning signals to look out for.
Puddles: If you happen to see out-of-place puddles forming beneath your vehicle, you most likely are experiencing transmission oil leakage.
Coloration: The transition of transmission oil from a lighter, transparent fluid (usually red, although in some vehicles the color will vary) to a deeper brown or dirty green color may be an important indication that the time has come to change the transmission oil.
Roaring noises: Whether you hear roaring noises while speeding up or when moving around tight corners, you may have a transmission problem. A transmission with depleted fluid can also create a buzzing or whining sound.
Chattering: When a vehicle chatters during takeoff, this is another typical indicator of depleted transmission oil. It can sound as though your vehicle is running over a rumble strip.
Warning light: Many new vehicles are outfitted with electronics that alert you if there is a problem with your transmission. If you see dashboard lighting that says “high transmission temperature,” it indicates that your transmission oil is hotter than is ideal. It’s also important to remember that your check engine light can illuminate if there is a problem with your transmission as well as your engine.
Difficulties shifting: Delays in shifting or difficulties shifting gears, such as sliding, slipping, bumps, and sounds may indicate a problem with the transmission oil.
Slipping of the transmission or engine revving while driving around corners: This is an indication that you are short on oil and there isn’t enough to hold the oil pick-up in the pan submerged.
Scent: A faint burning odor, particularly if it has an unpleasant tart odor, may be another indication that your transmission oil is faulty.
If you have questions about your transmission oil, you can conveniently verify its levels in most vehicles by removing the transmission dipstick. Refer to the operator’s manual to discover where to find the dipstick and what fluid quantities you should have.
However, some later model vehicles lack a dipstick, so it’s wise to search out a specialist mechanic who can raise the vehicle on a lift to inspect the fluid.
What will happen if a vehicle’s transmission oil runs out?
If your transmission fluid runs out entirely, your vehicle will generally not be able to get into gear, move only slightly, or will not shift at all. This is particularly true if you own a vehicle with an automatic transmission.
Allowing a car to run out of transmission fluid would almost certainly result in lengthy and expensive repairs. That’s why it’s important to be on the lookout for the above-mentioned warning signs! If in question, inspect your transmission or bring your vehicle to a specialist who can do it for you.
What exactly is a transmission flush?
When dealing with the topic of transmission maintenance, the word “transmission flush” is often mentioned.
A transmission flush, in essence, ensures that there is practically no old oil in the vehicle’s transmission, oil cooler, cooler lines, or torque converter. It’s an excellent method for removing grime and gunk that may get lodged in your transmission.
This servicing procedure employs a specialized system that extracts all of the existing, contaminated fluid from a transmission and replaces it with clean, fresh transmission oil, and in some cases, a cleaning solution is added to aid in the cleaning procedure.
Switching out old transmission oil with new oil and adding a new filter will help to extend the life of the transmission and prevent problems from occurring.
Make sure to follow the manufacturer’s recommendations when caring for your transmission. The consistency at which you change your fluid or get your transmission flushed can vary based on your particular vehicle and how you use it.
Selecting the correct transmission fluid
It can be difficult to determine what kind of transmission oil you need. To find the correct transmission oil, consult the user’s manual or the AMSOIL product guide.
AMSOIL Signature Series Synthetic Automatic Transmission Fluid and OE Synthetic Automatic Transmission Fluid are suggested for the majority of the market’s typical ATF specs. Signature Series is intended for use in transmissions operating under harsh situations such as hauling and towing. OE is ideal for the regular commuter.
So, what is transmission oil?
Transmission oil is an essential component of vehicle operation. While maintenance is easy to forget, make it a consistent part of your program to prevent inferior performance and excessive repair costs.