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Automatic & Manual Transmission Fluid: What’s the Difference?

Written by Charleen

Automatic Transmission Fluid & Manual Transmission Fluid: What’s the Difference?

John Baker|

Back in 2006, original equipment manufacturers (OEMs) offered buyers the choice between an automatic and a manual transmission in 47 percent of new cars. Fast forward to 2018, when only 2 percent of vehicles sold had a manual transmission, according to edmunds.com. 

Even with manual transmissions on the endangered species list, questions about automatic vs. manual transmission fluid still arise. Whether you opt for a stick or a slush box, you want to use the correct transmission fluid to maximize its performance and life.

Four responsibilities of a good automatic transmission fluid

The differences between automatic and manual transmission fluid lie in what each fluid must do. You don’t have to be an engineer to know that an automatic transmission is far more complex than a manual. Fittingly, so is the fluid it requires to function properly.

Automatic transmission fluid must perform several functions, including…

1. Act as a hydraulic fluid

Automatic transmissions use pressurized fluid to change gears. In essence, automatic transmission fluid is hydraulic fluid.

When your vehicle’s computer decides its time to shift gears, it sends an electric signal to the appropriate transmission solenoid. The solenoid directs fluid through a complex series of passages in the valve body to engage the correct gear. 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.

In a properly functioning transmission, this all happens instantly and goes largely unnoticed.

However, fluid that’s too thick (it’s viscosity is too high) can fail to flow quickly for crisp, confident shifts. That’s one reason automatic transmission fluid has a lower viscosity than manual transmission fluid.

Fluid that has accumulated foam can also fail in its role as a hydraulic fluid. The foam bubbles collapse under pressure, causing elongated or inconsistent shifts (not to mention gear wear). For that reason, automatic transmission fluid must contain foam inhibitors.

2. Deliver the correct frictional requirements

As noted, pressurized automatic transmission fluid squeezes the clutch packs together to engage the correct gears. These clutch packs are comprised of bare metal plates and plates coated in friction material. Engagement and disengagement must occur seamlessly to provide the driver with the best driving experience.

The fluid’s frictional properties determine whether this complicated choreography of moving metal and fluid creates crisp shifts or has you scheduling a time to change transmission fluid.

As such, automatic transmission fluid is formulated to provide precise frictional properties not required of manual transmission fluid.

Shop AMSOIL Synthetic Automatic Transmission Fluid

3. Protect gears from wear

Automatic transmissions contain an array of sun, planet and ring gears that require lubrication to protect against wear. The fluid must form a durable fluid film on metal surfaces to prevent metal-to-metal contact and wear.

4. Fight heat

Heat is automatic transmission fluid’s number-one enemy. It chemically breaks down the fluid (known as oxidation). Fluid that has broken down leads to sludge and varnish, which can clog narrow oil passages and contribute to clutch glazing. Soon, your vehicle can begin to shift hard, jerk or hesitate.

Automatic transmissions typically run hotter than manuals, meaning the fluid must provide enhanced protection against heat. That’s one reason some vehicles have automatic transmission fluid coolers.

Shop AMSOIL Synthetic Automatic Transmission Fluid

Three responsibilities of a good manual transmission fluid

Just because they’re less complex doesn’t mean manual transmission lubrication requirements are simple. A good manual transmission fluid must serve several roles, including…

1. Enable smooth shifts

Nothing connects vehicle and driver like a smooth-shifting manual gearbox. Enthusiasts won’t tolerate a transmission fluid that interferes with that link.

Here, we have some cross-over between automatic and manual transmission fluid. But they go about enabling smooth shifts differently based on different component architecture.

Most manual transmissions are equipped with synchronizers. As the name suggests, the synchro equalizes its speed with that of the gear being engaged, allowing a smooth shift. Without it, the gears spinning at different speeds would clash as they try to mate.

The synchronizer unit is comprised of two main components: the sleeve and the blocker or synchronizer ring. When the driver selects, for example, first gear, the sleeve moves to the first gear and locks onto the gear engagement teeth, also known as dogs. Depressing the clutch pedal and selecting second gear results in the sleeve moving the other way and selecting second gear in the same fashion.

Before the sleeve can lock onto the gear, the rotational speed of each must first be synchronized. The friction between the blocker ring and a cone on the face of the gear equalizes their speed, allowing gears to mate without clashing. The entire process happens quickly and goes unnoticed in correctly operating transmissions.

Lubricant viscosity plays a vital role in shift feel.

Viscosity that is too high could prevent shifting until the transmission warms up or result in abnormally high temperatures during operation. Viscosity that is too low could cause the synchronizer and dog gear to engage too quickly, resulting in grinding or hard shifts and abnormal transmission wear.

2. Fight wear

Again, manual transmission fluid must protect against wear, just like an automatic transmission fluid. Manual transmission fluid, as noted earlier, tends to be a higher viscosity than automatic transmission fluid. This helps the fluid develop a thick, durable protective film.

Shop AMSOIL Synthetic Manual Transmission Fluid

3. Protect brass synchronizers

Synchros are usually made of brass, which is softer than other metals. Certain lubricant additives aren’t compatible with brass and can damage the synchros.

The properly formulated manual transmission fluid for your vehicle will protect synchros to ensure they last as designed and promote smooth shifts.

As you may have figured out, automatic transmission fluid can, in some cases, work fine in manual transmissions. Which raises another question…

Will automatic transmission fluid work in a manual transmission?

Yes – provided the original equipment manufacturer recommends it. It’s important to check your owner’s manual to make sure before dumping ATF in your manual transmission.

In fact, some manuals may call for a gear lube or even a motor oil in older units.

I should also point out that continuously variable transmissions (CVT), popping up on more vehicles today due their increased efficiency, take their own fluid. And so do dual-clutch transmissions (DCT), which you’ll find on many sports cars.

Whichever you prefer, AMSOIL formulates a transmission fluid to help maximize transmission performance and life.

Shop AMSOIL Synthetic Transmission Fluid

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More AMSOIL Products Available in the Award-Winning Easy-Pack

Written by Charleen

The New EZ Pack is making waves! No more oil change Hassle

Jamie Gibson|

Sometimes an idea so great comes along it makes some wonder, “Why didn’t anyone think of this sooner?”

Case in point: AMSOIL easy-packs. Their innovative, flexible design has revolutionized the challenging task of changing fluids, reducing mess, waste and hassle.

Less Mess. Less Waste. Less Hassle.

After extensive research and testing to produce a concept worthy of the AMSOIL name, the AMSOIL SEVERE GEAR® Synthetic Gear Lube easy-pack launched in August 2018 to resounding success. It has earned rave reviews, a SEMA Global Media Award, a Flexible Packaging Achievement Award and the expectation that other companies will soon attempt to follow the AMSOIL lead once again.

Here’s what one customer says about the SEVERE GEAR easy-pack.

“175,000 trouble-free, heavy-haul miles. The new gear oil pouch makes it so easy to change diff fluid. Make the switch to AMSOIL today. Proven protection in the worst conditions.”

Nate the Hotshot
Laurel, Miss.

Since the launch of the AMSOIL SEVERE GEAR Synthetic Gear Lube easy pack, AMSOIL has expanded its easy pack offerings to include even more products. Check those out below and prepare for a new way of changing fluids with less stress and mess than what you’re used to enduring.

SEVERE GEAR Synthetic Gear Lube

Available in 75W-90, 80W-90, 75W-110 and 75W-140 viscosities, SEVERE GEAR is engineered for high-demand applications found in today’s autos/pick-up trucks, SUVs, heavy equipment and other hard-working vehicles. It delivers extreme-temperature performance no matter where the roads you travel happen to be.

Synthetic ATV/UTV Transmission and Differential Fluid

AMSOIL Synthetic ATV/UTV Transmission and Differential Fluid delivers severe-service protection against wear while riding aggressively or tackling tough terrain around your property. It protects heavily loaded, high-torque gears to promote long equipment life, even in extreme operating temperatures.

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Bonus: AMSOIL synthetic lubricants are Warranty Secure, keeping your factory warranty intact. Click here to learn more about your freedom to choose the lubricants you think best – and to score your free AMSOIL Runs on Freedom decal.

Synthetic Marine Gear Lube

AMSOIL Synthetic Marine Gear Lube is an exclusive AMSOIL formulation of synthetic base oils and high-performance additives that address specific concerns of marine applications. It is fortified with extreme-pressure (EP) additives for superior protection of fast-accelerating, high-torque/horsepower engines. It delivers advanced outboard protection against power loss and gear wear, even with up to 15 percent water contamination.*

*Based upon AMSOIL testing of AMSOIL Synthetic Marine Gear Lube 75W-90 in ASTM 3233 and ASTM D892.

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Signature Series Synthetic Automatic Transmission Fluid

Available in both Fuel-Efficient and Multi-Vehicle formulations, AMSOIL Signature Series ATF provides excellent wear protection and performance in today’s demanding transmission applications. Benefits include protection against thermal breakdown, cold-temperature fluidity, friction durability and maximum fuel economy.

Manual Transmission & Transaxle Gear Lube

AMSOIL Manual Transmission & Transaxle Gear Lube is formulated to meet the demands of towing, heavy hauling and performance driving typically found in manual transmissions. It delivers quick shifts and excellent wear protection in hot rods and muscle cars to promote smooth, fast engagement of synchronizers and gears. Its shear-stable formulation maintains viscosity and protects brass synchronizers while supporting equipment longevity.

Shop AMSOIL Easy Packs

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Remember This When Trying to Find Which Transmission Fluid You Need

Written by Charleen
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Remember This When Trying to Find Which Transmission Fluid You Need

John Baker|

Take a look at just a few of the dozens of automatic transmission fluid (ATF) specifications on the market:

  • ATF+4
  • Mercon V
  • Mercon LV
  • Dexron VI
  • ATF DW-1
  • ATF T-IV
  • SP-IV
  • Toyota ATF-WS
  • Honda DW (ZF
  • Diamond SP-IV

You’ve likely heard the term analysis paralysis.

That’s what many people feel when they scan the shelves at Advance Auto in search of transmission fluid. They just want a quart or two of ATF to top-off their vehicle, but instead they must decipher a series of hieroglyphics or face the specter of ruining their tranny by choosing the wrong fluid.

There’s a sure-fire way to avoid this hassle.

But first, check out this survey by the Petroleum Quality Institute of America (PQIA), which confirmed what many already know about buying ATF – the specifications listed on ATF labels can be confusing and misleading.

One reason is the sheer number of ATF specifications on the market. Interpreting the made-up words (“Mercon” and “Dexron” sound like diabetes medication or the latest U.S. Defense Department initiative, after all) leaves you shaking your head and vowing to service your transmission next spring.

It wasn’t always like this. At one time, Ford Mercon- and GM Dexron-type ATFs dominated the market and reduced your choices to a manageable few. Today, demand for those fluids has slipped below 50 percent and is declining as original equipment manufacturers (OEMs) continue to introduce their own, proprietary specs.

What is an ATF spec?

Simply put, it’s a set of performance standards. It’s not an actual fluid, meaning you don’t go to NAPA in search of Mercon or Dexron transmission fluid. You go in search of a fluid that meets the Mercon or Dexron specification. In an attempt to make it easy for you, many ATF manufacturers print those specs in giant letters on the label. Judging by the survey, though, it’s not working. This means the fluid was subjected to – and passed – a series of performance tests stipulated by the authors of the Mercon or Dexron specifications.

Today, it’s normal for most OEMs to author their own performance specifications rather than recommend using a fluid that meets a different OEM’s specifications, for example Mercon or Dexron. You can blame it on technological advancements that have made vehicles tougher on transmission fluid than cars of yesteryear. An automaker that introduces its latest 500-hp land rocket wants to be sure you’re using a transmission fluid capable of standing up to the intense heat and stress churning through all those gears.

It may also have something to do with money. Brand XYZ would rather you buy Brand XYZ transmission fluid than another company’s fluid, which helps explain why some OEM-branded fluids are so expensive.

That brings us back to analysis paralysis.

How can we cut through the confusion and make transmission fluid selection easy? And how do we do it while meeting the performance demands of most modern automatic transmissions?

One transmission fluid to rule them all

That’s a bit of hyperbole in honor of my favorite trilogy about hobbits and orcs, but it’s not far off.

We formulated AMSOIL Signature Series Synthetic Automatic Transmission Fluid and OE Synthetic Automatic Transmission Fluid to take the guesswork out of ATF selection. Both fluids are recommended for most of the common ATF specs on the market.

Mercon V? Check.

Dexron III? Check.

ATF+4? We cover that, too.

We take convenience a step further with our online Product Guide, which tells you which fluid your vehicle needs.

LOOK UP TRANSMISSION FLUID FO MY VEHICLE

If you tow, haul or engage in other types of severe service, use Signature Series Synthetic ATF. If you stick to the highway and mostly run to work and home, OE Synthetic ATF is your best bet.

So, when it comes to finding the right transmission fluid, forget about the hieroglyphics and just remember these six letters: AMSOIL.

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New Synthetic DCT Fluid Rounds Out AMSOIL Transmission Fluid Family.

Written by Ches Cain
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New Synthetic DCT Fluid Rounds Out AMSOIL Transmission Fluid Family.

AMSOIL DCT Dual-Clutch Transmission

The concept of two transmissions working in tandem within one vehicle dates back to the 1930s. The dual-clutch transmission (DCT) made its first practical appearance decades later in several 1980s-era race cars. In 2003, Volkswagen’s Golf* Mk4 R32 was the first production vehicle to feature the technology. Today the spectrum of vehicles with DCTs has widened, from the Hyundai Sonata* to the Nissan GT-R*.

Automatic and Dual-Clutch Transmissions

Traditional automatic transmissions have a defined set of planetary gears that engage based on vehicle speed. The correct gear is selected as the vehicle accelerates and decelerates. DCTs are automatic transmissions based on the architecture of manual transmissions. They consist of two manual transmissions in the same housing.  Most rely on computer-controlled, wet multi-plate clutches and do not require torque converters. DCTs provide more efficient shifts than traditional automatics because as one clutch is engaged the other readies the next gear. Properly maintained and lubricated the system delivers smooth, split-second shifts, the perfect complement to a powerful, high-performance engine.

While DCTs are capable of seamless shifts, they can suffer from shudder at low-speeds and during sustained acceleration. A transmission fluid that allows too much or too little friction can result in shudder, slipping or clashing. DCT fluid must also maintain the proper viscosity to provide protection during the high-heat operation native to high-performance sports sedans and super cars.

AMSOIL 100% Synthetic DCT Fluid

AMSOIL 100% Synthetic DCT Fluid is specifically engineered for sophisticated dual-clutch transmissions. Its perfectly balanced frictional properties protect against shudder and clashing to consistently produce fast, smooth shifts. Synthetic DCT Fluid’s exceptional durability provides stability in stop-and-go traffic and excels under intense, high-heat conditions. It promotes stable synchronizer engagements, extending the life of the transmission.

AMSOIL 100% Synthetic DCT Fluid (DCT)

  • Outstanding wear protection
  • Excellent performance in extreme heat and cold
  • Designed to prevent shudder

*All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are AMSOIL-engineered for use in the applications shown.

Sioux Falls Motor Oil and Lube News, Transmissions,

Common Fixes for a Transmission that Jerks or Hesitates

Written by Ches Cain
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Common Fixes for a Transmission that Jerks or Hesitates

AMSOIL Synthetic Automatic Transmission Fluid

Here are a few common reasons why your transmission may shift erratically, jerk or hesitate.

  • Low fluid level
  • Depleted fluid frictional properties
  • Poor cold-temperature fluidity

 

Start with the easiest fix

There’s an old adage when troubleshooting: start with the least expensive and simplest fix. In this case, check the transmission fluid level first. Low fluid can prevent the transmission from shifting properly. It’s important to find out why the fluid is low and fix any problems. It could be a leaky seal or other mechanical defect. Otherwise, adding new fluid won’t ultimately solve the problem.

Worn fluid equals poor shift quality

Transmission fluid that has aged and lost some of its frictional properties can also lead to poor shift quality. When your vehicle’s computer tells the transmission to shift 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. The fluid’s frictional properties play a vital role in ensuring the clutch plates bind together properly and gear shifts occur seamlessly. Over time, the frictional properties of the fluid can degrade, leading to elongated, jerky or inconsistent shifts. In this case, it’s time for a fluid change. How do you know for sure the fluid is worn? The only definite way to find out is to conduct used fluid analysis. However, fluid that smells burnt or appears dirty is likely due for a change. It’s best practice to change the fluid before the frictional properties are depleted and poor shifting is experienced since poor shifts can cause the clutches to wear more rapidly and lead to bigger issues that need mechanical repairs.

Be aware of “adaptive” transmissions

One interesting note affects newer vehicles equipped with adaptive transmissions. These units “learn” your driving habits and the characteristics of the fluid to adjust shifts accordingly. As the fluid loses its frictional properties, the computer compensates and adjusts transmission performance. If you’ve recently changed your fluid, the computer may still operate as if old fluid is installed, causing poor shift quality. In these cases, keep driving and eventually the computer will “relearn” your driving habits and the behavior of the new fluid and adjust accordingly. The problem was significant enough on some 2012-2013 Ford F-150s to cause Ford to issue a technical service bulletin (TSB 13-1-10).

 

Your transmission fluid’s frictional properties are vital to best performance

Comparison of Frictional Properties - ATF

To demonstrate its outstanding performance, AMSOIL Signature Series Synthetic Automatic Transmission Fluid was tested in taxi cabs operating in the intense heat of Las Vegas. First, the frictional properties of new fluid were tested. Then, after more than 180,000 miles of work in a fleet of taxis, the fluid was tested again. As shown in the graph, the fluid maintained nearly identical frictional properties to new fluid after 180,000 miles of severe service. That translates into solid, confident shifts day after day and long transmission life.

 

Cold weather can reduce shift quality

When the temperature drops, transmission fluids with poor cold-flow properties can thicken and cause elongated and hard shifts until the fluid has warmed up enough to flow properly. Switching to a high-quality synthetic transmission fluid will help. Synthetics don’t contain waxes, as conventional fluids do, so they remain fluid at lower temperatures for improved shifts during cold weather.

The best transmission fluid available won’t fix a broken transmission. But using high-quality synthetic transmission fluid can help improve shift quality and maximize transmission life.

Sioux Falls Motor Oil and Lube News, Transmissions, , , , ,