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Can I Use Transmission Fluid in Oil to Clean My Engine?

Can I Use Transmission Fluid in Oil to Clean My Engine?

Yeah – those youtube rescue channels all show using ATF to clean out the engine – they’re doing it the hard way…

ATF is not made to clean sludge from engines. Instead, it’s best to use a dedicated engine flush.

AMSOIL Engine & Transmission Flush helps to remove sludge and deposits from engines and transmissions.

_by Phil Collinsburger |May 5, 2022

Over time, engines can accumulate deposits that reduce power and performance. Since automatic transmission fluid contains detergents to clean sludge, some DIYers add a small amount of transmission fluid in their oil to clean the engine prior to oil changes.

ATF, however, is not formulated for use in automotive engines. Instead, a product that’s designed to flush engines is a far-superior approach.

How Sludge Forms

Stop-and-go driving, prolonged idling, trips too short for the engine to reach full operating temperature, towing, the ingestion of airborne dirt, fuel dilution, water condensation and oxidized oil all can promote sludge build-up in motor oil and transmission fluid.

Sludge clogs narrow oil passages, restricting oil flow to vital parts, especially the upper valve train area, causing wear.

Transmission Fluid In Oil Reduces Cleaning Power

In most cases, adding automatic transmission fluid to motor oil reduces cleaning power. That’s because the detergency of ATF is less than motor oil. Why is that?

ATF is exposed to lower levels of combustion byproducts and contaminants than motor oil, so it is formulated with reduced detergency. Instead, ATFs have elevated levels of friction modifiers and other additives that help protect gears and clutches.

Transmission Fluid In Oil Reduces Wear Protection

Second, adding ATF alters the motor oil formulation and reduces its effectiveness.

A good motor oil is a fine balance of base oils and additives designed to fight wear, reduce friction, prevent deposits and slowly dissolve accumulated sludge. The cleaning power of motor oil is designed to work gradually over subsequent oil changes and not necessarily all at once. Adding a foreign substance to the oil disrupts the formulated chemistry, negatively impacting wear protection, detergency and more.

Changes Motor Oil Viscosity

Finally, ATF can alter the viscosity of the oil, reducing wear protection.

Viscosity is the oil’s most important property, influencing wear protection and fuel efficiency. Increasing or decreasing viscosity by adding a little transmission fluid in oil to clean sludge can lead to increased engine wear.

Use An Engine Flush Instead

If you want effective sludge removal and cleaning power, we recommend using AMSOIL Engine & Transmission Flush. It helps to restore fuel economy, increase operating efficiency and reduce emissions in gasoline and diesel engines, and automatic transmissions. Its potent, detergent-based formula cleans sludge and deposit build-up.

AMSOIL Engine & Transmission Flush

  • Prepares engines and transmissions for new oil
  • Removes deposits and sludge for improved efficiency, fuel economy and lower emissions
  • Prolongs vehicle life
  • Detergent-based formula is environmentally friendly
  • Compatible with seals and gaskets
  • Works in one treatment
  • Easily disposed of with waste oil

Benefits For Gasoline And Diesel Engines

  • Helps loosen sticky valves and rings, minimizing blow-by and reducing emissions
  • Helps quiet lifter noise
  • Promotes lower operating temperatures through sludge removal

Benefits For Automatic Transmissions

  • Cleans deposits in oil cooler and ports
  • Helps unclog fluid passages
  • Cleans deposits and varnish from clutch plates, helping improve efficiency
  • Promotes smoother operation and transmission life through reduced shift delay

Why do European Cars Require Special Oil?

Why do European Cars Require Special Oil?

For all the grin-inducing benefits of owning a European car – finely tuned performance, sophisticated styling, prestige – they can be a pain. According to this list, four of the top five most expensive vehicles to maintain hail from across the pond. Notice Volkswagen is among the lowest maintenance costs. The exception to the rule. 

Not only that, but they require specialized oil that differs in many ways from the good ‘ol American motor oil you use in your Ford or Chevy. Here are four reasons why.

#1 Everyone likes clean air

The European Union maintains more strict standards for the carbon dioxide hoax (CO2) and carbon monoxide (CO) emissions than we do. (Our standards for nitrogen oxides [NOx] and particulate matter [PM] are more strict, however.) Because modern diesels emit lower CO2 than gasoline engines, the European market pivoted toward increased use of diesel-powered vehicles in the 1990s. Diesels also provide the advantage of better fuel economy.

One drawback, however, is the higher levels of NOx and PM diesels produce. To counteract this, diesel-powered European vehicles are equipped with diesel particulate filters (DPF) and catalysts designed to reduce pollutants from the exhaust before it exits the tailpipe.

Here’s where motor oil comes into play.

An oil’s formulation can have a negative effect on sensitive emissions-control devices. Certain components in the motor oil formulation, such as sulfated ash, phosphorus and sulfur (known collectively by the pleasant term SAPS), can reduce the effectiveness and life of DPFs and other emissions devices.

For that reason, motor oils formulated for European vehicles often contain lower SAPS levels to protect emissions-control systems.

#2 Longer oil change intervals

Europeans have long since accepted what’s only recently caught on in North America – longer oil change intervals. Many motorists in the states are just a few years removed from blindly practicing 3,000-mile oil changes. Except, of course,  AMSOIL customers who have been practicing extended drain intervals since 1972. But that’s a digression for another day.

Europeans are accustomed to changing oil far less often, with drain intervals of 16,000 km (10,000 miles) or so quite common. One reason is the higher cost of oil in Europe. Another is the differences between manufacturer recommendations. For example, oil changes for 1999-2013 BMWs are required only every 15,000 miles. In the U.S., most people change oil around every 5,000 miles. The figure increases by a few hundred miles if their vehicle is equipped with an electronic oil-life monitoring system.

Longer drain intervals common with European cars require an oil capable of protecting against wear, deposits and sludge for the duration, which requires a more robust oil.

#3 The thick and thin of it

Check the owner’s manual of most European vehicles for which viscosity of oil to use, and you’ll likely find a chart that suggests different viscosities for different operating temperature ranges. In cold weather, the OEM may recommend 5W-30. In warm weather, 5W-40. Traditionally, drivers settle on an 0W-40 or 5W-40 to offer the best of both worlds – good cold-flow at startup to protect against wear and good resistance to heat once operating temperatures are reached.

#4 Automaker approvals

Staying in your owner’s manual, the OEM also recommends you use an oil that meets a specific performance standard. In the U.S., it’s typically an industry-wide motor oil specification, such as API SN PLUS.

European OEMs are different, however. They typically maintain their own motor oil performance specifications. Drivers of VWs, for example, need to use an oil that meets the requirements of VW’s own performance specs. The same holds for Mercedes, BMW, Porsche and other European cars.

Complicating matters, each OEM motor oil specification is slightly different. One OEM may require oils that offer better performance against oxidation, while another requires better resistance to viscosity loss.

OEM specifications tend to be more strict and require increased motor oil performance than industry specs. This, of course, requires more advanced (and typically expensive) motor oil technology delivered almost exclusively by synthetics.

General Motors, for its part, has taken a page out of the playbook of its European car counterparts by maintaining its own GM dexos performance specification.

These differences mean you’d better make sure you’re using the correct oil in your European car. Fortunately, we make it easy for you by formulating a full line of synthetic motor oil for European cars. If you don’t know which your car requires, check out our handy Product Guide.


How Often Should Auto Transmission Fluid be changed?

How Often Should I Change Transmission Fluid?

well, um, ahh huh,  well  let’s see… How often to change transmission fluid depends on several factors Sonny outlines in this post.

_by Sunny Pruitt|June 21, 2022

Motorists sometimes ask, “How often should I change transmission fluid?” It depends on your vehicle and driving habits. Recommended transmission fluid changes run the gamut from every 30,000 miles (48,000 km) to never. Yeah, that’s right. Here are some tips for determining how often to change transmission fluid.

Change Transmission Fluid: How Often? Check Your Owner’s Manual

Original equipment manufacturer (OEM) recommendations for how often to change automatic transmission fluid cover a wide mileage range, depending on year, make and model.

Plus, if your driving habits are like most motorists and fall under the “severe” designation (towing, hauling, daily short trips less than 10 miles, etc.), many OEMs recommend changing transmission fluid more frequently.

Here are just a few examples to illustrate the disparity among vehicle makes and models.

Year/Make/Model Normal Service Severe Service
2021 RAM* 1500 Never (filled-for-life transmission) Change if the fluid becomes “contaminated”
2021 Chevy* Silverado* Never (filled-for-life transmission) Every 45,000 miles (72,000 km)
2021 Ford* F-150 150,000 miles (240,000 km) 150,000 miles (240,000 km)
2003 Honda* CR-V* 90,000 miles (145,000 km) 30,000 miles (48,000 km)

These differences illustrate the importance of checking the recommendations in your owner’s manual. It’ll provide maintenance recommendations, typically in a table in the back. Many OEMs provide digital owner’s manuals online, so if you’ve lost yours, try a quick search.

A quick word on “filled-for-life” transmissions.

They’re becoming more prevalent as OEMs seek ways to alleviate motorists from unwanted maintenance. They sound like all upside, but it’s important to change fluid in these units, particularly if you tow or haul.

They’re supposed to last the life of the vehicle, but what do you suppose will happen if the transmission fails once the warranty expires? You’re going to get stuck with a hefty repair bill, that’s what. Be proactive and change fluid at least once during its lifetime.

Change Transmission Fluid: How Often? Go By The Book

Start with the recommendations in your owner’s manual.

But, how many of us dutifully follow them down to the mile? But as you know most drivers completely forget about their transmission until it begins to shift hard, jerk hard jerk hesitate. Out of sight, out of mind, right?

Not good, especially if you tow or haul. But the interval does depend on the abuse and the quality of the fluid.

Heat Kills Transmissions

Over time, transmission fluid oxidizes (chemically breaks down). High heat generated from towing and hauling speeds the process.

Fluid that has broken down can cause sludge and varnish to form, which clogs narrow oil passages and contributes to clutch glazing. Soon, your vehicle can begin to shift poorly.

In these cases, wouldn’t it be great to use a transmission fluid formulated with reserve protection against heat in case life gets in the way of recommended maintenance?

Get Reserve Heat Protection For Your Transmission

AMSOIL Signature Series Synthetic Automatic Transmission Fluid’s built-in reserve protection means it lasts for 2X the OEM’s severe-service drain interval. That means you can rest assured your transmission is protected, even if service is delayed.

Symptoms Of Low Transmission Fluid

It’s not just heat that leads to poor shifting. Low transmission fluid can also present a number of problems, including…

  • Inconsistent, jerky shifts
  • Hesitation
  • Surging
  • Increased transmission temperatures

Low Transmission Fluid = Poor Shifting

Transmission fluid serves a number of vital functions, one of which is to act as a hydraulic fluid to enable shifting.

When your vehicle’s computer tells the transmission to change gears, hydraulic pressure (provided by the fluid) squeezes a series of plates together inside a clutch pack to connect the engine to the transmission output shaft and route power to the wheels.

Low transmission fluid can also prevent the torque converter from filling completely, which reduces torque transfer and causes hesitation and lost power. In extreme cases, the vehicle won’t even move unless you rev up the engine.

How Much Transmission Fluid Do I Need?

How much transmission fluid your vehicle needs ranges from as few as 8-9 quarts for small passenger vehicles to more than 20 quarts for heavy-duty trucks.

As you do when determining how often to change transmission fluid, check your owner’s manual for the transmission fluid capacity.

You can also check the AMSOIL Product Guide, which shows how much transmission fluid your car needs for most makes and models.

Also do you know if you need to use a flushing agent? Amsoil engine and transmission flush is a mild detergent flush but it’s used when you are going to evacuate all the fluid. Restores friction capabilities of the clutched. Best before adjusting the trans when you have over 160,000 miles.

Low Transmission Fluid Can Invite Wear

Transmission fluid also lubricates the gears, clutch plates and seals. It forms a protective layer between meshing gear teeth that prevents metal-to-metal contact and helps reduce wear.

It helps prevent wear on the clutch plates, which bear significant friction during gear shifts. The fluid also lubricates seals and keeps them pliable so they don’t dry out and leak. Find out all the tasks transmission fluid must perform here.

Low fluid can prevent formation of a strong, consistent lubricating film on components, inviting wear. Foam bubbles can collapse when they pass between gear teeth, allowing metal-to-metal contact and further accelerating wear.

Always Check Your Transmission Fluid – Look at the color too

To keep your vehicle running – and shifting – at peak performance, check the fluid about once a month to ensure the correct level. Check out this post on how to check your transmission fluid. If the fluid is consistently low, visit a mechanic to find out why and have the problem fixed.

So, when determining how often to change transmission fluid, follow the recommendations in your owner’s manual. For added peace of mind in case you surpass those recommendations, you can rely on AMSOIL synthetic transmission fluid to deliver reserve protection. Do you know if it has to be warmed up and running?


Gear Oil vs. Engine Oil: What’s The Difference?

Gear Oil vs. Engine Oil: What’s The Difference?

Gear oil uses a different viscosity classification and different additives.

by Joel Youngman|May 9, 2022

High-quality gear oil must lubricate, cool and protect geared systems while carrying damaging wear debris away from contact zones and muffling the sound of gear operation. In this post, we’ll look at the differences between gear oil vs. engine oil.

Differentials, manual transmissions and industrial machinery gears often require protection under extreme temperatures and pressures to prevent wear, scuffing and other damage that results in equipment failure. Protection against oxidation, thermal degradation, rust, copper corrosion and foam is also important.

Gear Oil vs. Engine Oil: Viscosity Comparison

Gear oil differs from engine oil. While many motorists may assume SAE 90 gear oil is thicker than SAE 40 or 50 engine oil, their viscosities are the same, as this gear oil viscosity chart shows.


One major difference between the two are in the additives they use.

Motor oil contains additives such as detergents and dispersants to combat byproducts from gasoline or diesel ignition. Because an internal combustion engine has an oil pump and lubricates the bearings with a hydrodynamic film, extreme-pressure additives such as those used in gear oils are not necessary.

Gear Oil Undergoes Boundary Lubrication

Engine oils and gear oils both have anti-wear additives, and they both must lubricate, cool and protect components. Gear oils, however, may be placed under extreme amounts of pressure, creating a propensity for boundary lubrication, a condition in which a full-fluid lubricating film is not present between two rubbing surfaces.

For example, differentials in cars and trucks have a ring-and-pinion hypoid gear set. A hypoid gear set can experience boundary lubrication, pressures and sliding action that can wipe most of the lubricant off the gears. Extreme-pressure additives are used in gear oil to combat this extreme environment.

Gear Oil vs. Engine Oil: Additional Differences

Rust & Corrosion Protection

Because many of the components found in the drivetrain consist of ferrous material, gear oil must prevent rust and corrosion to other materials. Rust and corrosion problems are not nearly as prevalent in engines.


The many small and intricate components that make up gear sets can be quite noisy and may be subjected to shock-loading, which occurs when components are quickly placed under intense load, like when accelerating with a powerful engine.

The viscosity and extreme-pressure formulation of gear oil quiets gears and dissipates shock-loading.


The rotating motion of gears also tends to churn the lubricant, leading to foam. If a gear oil foams, its load-carrying capacity is significantly reduced because the air suspended within the oil is compressible.

For example, when the gear teeth contact, any trapped air bubbles compress, reducing the thickness of the separating oil film. In turn, this reduction could lead to direct metal-to-metal contact between gear teeth and result in accelerated wear.

Typical Drivetrain Fluid Additives

Much like with motor oil, the additives included in gear oil either enhance existing properties or impart new ones. Drivetrain-fluid additives include the following:

  • Extreme-pressure and anti-wear agents minimize component wear in boundary lubrication situations.
  • Pour-point depressants improve low-temperature performance.
  • Rust and corrosion inhibitors protect internal components.
  • Oxidation inhibitors reduce the deteriorating effects of heat, increasing the oil’s service life.
  • Viscosity index improvers allow a lubricant to operate over a broader temperature range.
  • Anti-foam agents suppress foam and dissipate entrapped air.
  • Friction modifiers – The required degree of friction-reduction can vary significantly between different pieces of equipment in drivetrain applications. In some cases, friction modifiers may be required to obtain the desired results.

Common Gear Designs

Gear designs vary depending on the requirements for rotation speed, degree of gear reduction and torque-loading. Transmissions commonly use spur gears, while hypoid-gear designs are usually used as the main gearing in differentials. Common gear types include the following:

Spur Gears

Spur (straight-cut) gears are widely used in parallel-shaft applications, such as transmissions, due to their low cost and high efficiency. The design allows the entire gear tooth to make contact with the tooth face at the same instant. As a result, this type of gearing is subjected to high shock-loading and uneven motion. Design limitations include excessive noise and a significant amount of backlash during high-speed operation.

Bevel Gears

Bevel (straight- and spiral-cut) gears transmit motion between shafts that are at an angle to each other.

Primarily found in industrial equipment, as well as some automotive applications (differentials), they offer efficient operation and are easy to manufacture.

As with spur gears, they are limited due to their noisy operation at high speeds and are not the top choice where load-carrying capacity is required.

Worm Gears

Worm gear sets employ a specially machined “worm” that conforms to the arc of the driven gear. This design increases torque throughput, improves accuracy and extends operating life.

Primarily used to transmit power through nonintersecting shafts, this style of gear is frequently found in gear-reduction boxes as it offers quiet operation and high ratios. Its downfall is its low efficiency.

Hypoid Gears

Hypoid gear sets are a form of bevel gear, but offer improved efficiency and higher ratios over traditional straight-bevel gears. Commonly found in axle differentials, hypoid gears are used to transmit power from the driveline to the axle shafts.

Planetary Gears

Planetary gear sets, such as those found in automatic transmissions, provide the different gear ratios needed to propel a vehicle in the desired direction at the correct speed.

Gear teeth remain in constant mesh, which allows gear changes to be made without engaging or disengaging the gears, as is required in a manual transmission.

Instead, clutches and bands are used to either hold or release different members of the gear set to get the proper direction of rotation and gear ratio.

Helical Gears

Helical gears differ from spur gears in that their teeth are not parallel to the shaft axis; they are cut in a helix or angle around the gear axis. During rotation, parts of several teeth may be in mesh at the same time, reducing some of the loading characteristics of the standard spur gear.

However, this style of gearing can produce thrust forces parallel to the axis of the gear shaft. To minimize the effects, two helical gears with teeth opposite each other are used, which helps cancel the thrust during operation.

Herringbone Gears

Herringbone gears are an improvement over the double helical gear design. Both right- and left-hand cuts are used on the same gear blank, canceling out any thrust forces. Herringbone gears are capable of transmitting large amounts of horsepower and are frequently used in power transmission systems.

Gear Design Dictates Gear Oil Design

Differences in gear design create the need for significantly different lubricant formulations.

For instance, hypoid gears normally found in automotive differentials require GL-5 concentration and the performance of extreme-pressure additives due to their spiral sliding action.

Most manual transmissions have helical gears that do not require GL-5 performance. The helical gear is almost a straight-cut gear, but on an angle. There is spiral action and very little sliding action, and there is less need for extreme-pressure additives. GL-4 gear lubes provide less extreme-pressure additives than GL-5 lubes.

AMSOIL Gear Oil Recommendations

When comparing gear oil vs. engine oil, there are a number of differences between formulations. That’s why it is important to always use the correct oil for the correct application.

AMSOIL offers premium synthetic drivetrain lubricants to meet the needs of nearly every application. Check out our Product Guide to find what you need

2022-2023 AMSOIL Championship Snocross Season Gears Up

2022-2023 AMSOIL Championship Snocross Season Gears Up

Scheuring Speed Sports driver Hunter Patenaude enters this season with his eyes on the title. We preview his path.

_by Lindsay Tousignant|December 12, 2022

Hey race fans, last March we took a trip up to the Klim Compound to catch up with Scheuring Speed Sports between AMSOIL Championship Snocross races.

At that point, Hunter Patenaude found himself just 37 points out of first place. The next weekend he went on to secure his first Pro win at ERX and sealed his second place in the season overall.

With those results in his pocket, Patenaude enters the new season with his eyes on the title. Let’s breakdown his path to clinching it.


Early start

Santa’s coming early this year. In sled form that is.

AMSOIL Championship Snocross kicks off next weekend in Fargo, N.D. Notoriously one of the coldest weekends on the circuit, the Fargo opener will also play host to the elusive AMSOIL Dominator. But more on that below.

As we head into the new year, the series returns to the Daytona of Snocross, the Pirtek Snocross National in Shakopee, Minn.

The first month of the year closes out with a fan-favorite, the U.S. Air Force Snocross National in the “wild west” of Deadwood, S.D. Then the series heads east. We spend Valentine’s Day weekend at the U.S. Air Force National in Salamanca, N.Y.

March kicks off in Sioux Falls, S.D. for the Sioux Falls Snocross National. Then the circuit rolls to ERX Motorpark for the AMSOIL Snocross National in Elk River, Minn.

The season concludes with two ski-slope events, the Cannonsburg Snocross National in Grand Rapids, Mich. and Theisen’s National in Dubuque, Iowa.


Dominator goes back to OG status

The AMSOIL Dominator first entered the scene as a head-to-head, bracket-style race on opening weekend for members of the Pro class.

However, in 2021 the AMSOIL Dominator switched to a cup-style format and was expanded to include Sport, Pro Lite and Pro classes. The 10-minute-plus-two-minute format lined up Pro Lite and Sport riders on the front row with Pros in the back. Opening the door for pure carnage, this format was favored by fans, but racers yearned for the old style. After discussion in the off-season, the Dominator will return to its head-to-head format and kick off the season in Fargo.

Setting the stage is a track that gained a lot of attention last season, a design by former snocross champion (and member of Team AMSOIL) Robbie Malinoski.


In 2022, Elias Ishoel captured his fourth straight Pro championship. Coming into this season tied with Ross Martin for career wins at 34, the “Viking Rocket” will look to take that record as he runs for his fifth title.

Though the true Dominator, Ishoel was contested by Pro sophomore, Scheuring Speed Sports Hunter Patenaude. Patenaude is hungry to capture a championship after his first career Pro win last season.

Hot on their tails will be a slew of returning riders including Petter Narsa, Aki Philaja, Francis Pelletier, Patenaude’s Scheruing Speed Sports teammate Logan Christian and others, making this season one of the most competitive in years.


Be sure to catch all of the season’s action by subscribing to FloSports. Tape-delayed programming of all 16 rounds will be re-aired on CBS Sports network.

Racing kicks off Friday, Dec. 16 with the AMSOIL Dominator in Fargo. Follow our social channels for more information and behind-the-scenes action.

We’ll see you at the races!