“CVT” stands for continuously variable transmission. A CVT transmission uses a pair of variable-diameter pulleys and a belt or chain to provide unlimited gear ratios.
How does a CVT work?
To illustrate, think of a traditional automatic or manual transmission. They’re built with a defined number of gears, for example first through sixth (plus reverse). The transmission can operate in only one gear at a time. You typically feel a slight surge with each gear change.
CVTs, however, offer unlimited gear ratios.
Take a look at the image. You can see the metal belt connecting the two pulleys. Depending on engine speed and load, the computer automatically varies the pulley sizes to ensure the optimal gear ratio for the driving conditions.
CVTs use variable-diameter pulleys to create unlimited gear ratios.
CVT transmission pros and cons
What good does that do?
Imagine pedaling a bike. As you approach a steep hill, you adjust the shifters so a smaller chainring attached to the pedals is driving a larger sprocket on the rear wheel. This reduces the effort required to move the bike.
When you reach a stretch of flat road, you adjust the gear ratio again so a larger chainring attached to the pedals is driving a smaller sprocket. This helps achieve the perfect balance between energy expended and bicycle speed.
The same principle applies to a CVT, except the computer does all the thinking for you. When starting from a dead stop, it varies the pulley diameters (smaller drive pulley and larger driven pulley) so the engine can move the car as efficiently as possible. As you accelerate, it continuously varies the pulley sizes to keep the engine in its “sweet spot,” which results in improved fuel economy. Plus, you never feel the gear engagements because, in effect, there aren’t any.
CVTs gaining in popularity – but there are negatives
These benefits are why many car makers, including Nissan, Honda and Toyota are introducing more vehicles with CVTs.
There are drawbacks, however, including the “rubber-band effect” (you rev the engine, yet it takes a moment for vehicle speed to catch up) and lack of driver involvement (zero fun). In addition, most CVTs’ relatively diminutive parts can’t handle the power and torque of the truck or SUV you use to tow your boat or camper, which is why you find them mostly on smaller cars. Although there are some exceptions, as the list shows, which shows popular vehicles with a CVT.
What cars have a CVT transmission?
Honda Accord
Honda HR-V
Mercedes-Benz A- and B-Class
Nissan Altima
Nissan Pathfinder
Subaru Forester
Subaru Impreza
Subaru Legacy
Subaru Outback
Toyota Camry
Toyota Highlander Hybrid
Toyota Prius
Slip into something special
One look at the guts of a CVT and you can’t help but wonder how the belt doesn’t just slip wildly over the pulleys.
Believe it or not, the transmission fluid plays a major role in ensuring the belt or chain remains in contact with the pulleys without slipping.
That’s why CVTs require specialized CVT transmissions fluids, and not the traditional automatic or manual transmission fluid you probably have in your garage. CVT transmission fluids must be formulated with the correct frictional requirements to guard against slipping. Using the wrong fluid will reduce performance and potentially wreck your transmission.
Wear protection also important
Solid wear protection is also vital to maximizing CVT performance and life. That’s why we designed AMSOIL Synthetic CVT Fluid to fight wear and help extend transmission life.
To demonstrate, we pitted AMSOIL Synthetic CVT Fluid against Nissan NS-2 CVT Fluid in a field trial. After 100,000 miles, the belt lubricated with AMSOIL Synthetic CVT Fluid demonstrated minimal wear, as you can see in the images. This helps you get the best performance and most life out of your CVT.
AMSOIL Synthetic CVT Fluid protected against wear.
The belt lubricated with Nissan NS-2 CVT Fluid demonstrated increased wear.
While driving purists may initially scoff at the notion of a transmission that requires no driver input, many eventually warm up to CVTs’ increased gas mileage and smooth operability.
If you’re one of them, make sure you protect it with a good CVT transmission fluid.
Friends of mine in Minneapolis were driving on Highway 35, talking about this and that, minding their own business, when – wham! A trailer carrying a boat slammed into their car.
The trailer had disconnected from the tow vehicle and darted across the median in a high-velocity trajectory that could have killed my friends had it not been a glancing blow. Though the shattering glass put them in the hospital, it could have been much worse.
It was an accident that shouldn’t have happened.
Safety tips for towing a trailer
One morning while driving to work I was thinking about this very topic and, right in front of me, I saw another towing accident. Someone towing his race car down Mesaba Ave. here in Duluth, Minn., caused a traffic jam when the stock car left the trailer and swept wildly into the midst of rush-hour traffic.
Again, it was an accident that shouldn’t have happened.
Whether it’s a boat, a house trailer or your trash to the dump, safely towing a trailer requires attention to detail.
Here are nine key points for safe trailer towing and long vehicle life
1) Know your weight limits
Make sure your trailer and whatever you’re hauling fall within the towing or hauling capacities of your vehicle. Check the owner’s manual to find the trailer types that your vehicle can haul and the maximum weight it can pull. Use the right trailer hitch and make sure it is hitched correctly.
2) Distribute weight evenly
If your trailer fishtails, back off the gas and see if it stops. If it continues when you accelerate again, check to see how the weight is distributed on the trailer. It may not be distributed evenly from side to side, or else it’s too far back to place sufficient load on the hitch ball.
Pro Tip: Try to carry 5-10 percent of the trailer load on the hitch. Redistribute the load as necessary before continuing.
3) Ensure the trailer lights work
Connect the brake and signal lights. Double check to make sure the trailer’s brakes, turn signals and tail lights are synchronized with the tow vehicle.
4) Properly inflate the tires
People I once knew suffered 17 tire blowouts while pulling a trailer from California to south Texas (true!). You’d think they would have figured out they had too much weight in the trailer.
In addition to staying within weight limits for your rig, be sure the tires are in good condition and properly inflated. Be sure to check your wheel bearings, too. An overheated bearing will sideline your rig as fast as a flat tire. Check out this video on bearing maintenance.
5) Know that your vehicle will handle differently
When towing, you’re operating a vehicle combination that’s longer and heavier than normal. Be sure to adjust your driving practices accordingly.
Backing up is tricky, but it’s a skill you can learn. Until you’re experienced, have someone direct you from outside in those tight spots or places where you have limited visibility.
Avoid sudden turns. I know – sounds obvious. But I was once the first person to an accident where someone decided at the last minute to take the exit instead of going straight. The car ended up upside down because the trailer had other ideas.
When it comes to towing accidents, don’t say, “It can’t happen to me.” Say instead, “It must not happen to me.”
It’s a simple matter of physics. When towing, you have more momentum than you would without a trailer. Remember that stopping requires more time and distance. Avoid tailgating and pay attention to what’s happening a little farther down the road than you normally would.
8) Keep your head on a swivel
Maybe you forgot to fasten a chain, secure the hitch or tie down your payload properly. If you’re in a hurry to get home after a long trip, things like that can happen.
Once you’re on the road, frequently check your mirrors to make sure everything looks good back there. I know a boat owner whose yacht fell sideways on the highway halfway between Canada and Duluth, which is the middle of nowhere for those who’ve never been there. It turned out something wasn’t fastened properly.
9) Upgrade your transmission protection
Towing places enormous stress on a transmission. In fact, because of the intense heat, towing is probably the number-one killer of transmissions.
For this reason, the “towing package” on many trucks includes a transmission-oil cooler. It also helps to use a high-end synthetic lubricant. Synthetics reduce friction and provide better resistance to high heat, helping the tranny run cooler, shift confidently and last longer.
Shameless plug time: AMSOIL Signature Series Synthetic ATF handles heat so well, you can confidently double your vehicle manufacturer’s severe-service drain interval in passenger cars and light trucks.
What’s up with these “Filled-for-Life Transmissions”?
John Baker|
Casual motorists generally take no interest in crawling under their vehicles on a Saturday afternoon. And, when was the last time you heard someone express excitement over dropping their car off at the dealership for maintenance?
The automakers know this, which explains the proliferation of sealed, or filled-for-life, transmissions and differentials. Many vehicles also use “lifetime” factory fill fluids in these components that supposedly don’t require changing. Some transmissions and differentials don’t even include dipsticks or access plugs for checking the fluids.
The dirty little secret is that “filled-for-life” really means “filled for the life of the warranty.”
Suppose the “filled-for-life” transmission or differential on your truck fails after the factory warranty has expired. What do you think the dealership is going to do? That’s right – slide a bill across the counter to the tune of several thousand dollars.
It’s a good idea to change fluids in a filled-for-life or sealed transmission or differential at least once during its lifetime, and more often if you tow or haul. Here’s why.
Big power = increased heat
Modern vehicles are tougher on transmission fluid and gear lube than ever. For starters, the automakers are in an endless arms race to produce more power than the competition. All that added power has to go through the transmission and differential before reaching the wheels, yet modern transmissions are smaller and lighter than their predecessors. Meanwhile, the gears and bearings in most differentials remain unchanged despite the increased power they must handle.
This adds up to increased heat, and heat is one of the transmission fluid’s biggest enemies. It speeds the oxidation process and causes the fluid to chemically break down. Fluid that has broken down can cause sludge and varnish to form, which clogs narrow oil passages and can lead to stuck valves. Soon, your vehicle can begin to shift hard, hesitate or quit shifting altogether.
The situation is just as dire downstream of the tranny where heat and pressure wreak havoc inside the differential. Towing and hauling increase friction, which in turn increases heat. Extreme heat causes the gear lube to thin, reducing the effectiveness with which it keeps gear teeth separated and prevents wear. Thinner gear lube further increases friction, which causes heat to increase in a vicious cycle known as “thermal runaway.”
Lighter fluid, and less of it
Components also use lower-viscosity fluids to help boost fuel efficiency. That translates into thinner fluid protecting against intense heat and wear – not an easy task. In addition, many automakers use less gear lube than before to help reduce energy lost to friction and boost fuel economy.
Given such challenging conditions, what’s the best way to combat heat and stress to ensure your vehicle keeps running strong? Never change the fluids? Hardly.
“Filled-for-life” is misleading
In fact, your “lifetime” fluid may require changing if your driving habits full under the “severe” designation, which includes towing and hauling.
The differential in the 2016 Ford Super Duty 250, for example, is considered “filled for life.” However, the owner’s manual instructs you to change the fluid every 50,000 miles (80,467 km) in “severe” conditions and anytime the differential is submerged in water.
Did you hear that, anglers?
The 2017 Toyota Tundra likewise features a “filled-for-life” differential. But Toyota tells you to change fluid every 15,000 miles (24,140 km) if towing.
Complicating matters, some vehicles don’t even include a service schedule for changing transmission fluid. The Mazda CX-5 is one example. That doesn’t seem like a great idea if you plan to keep the vehicle past its factory warranty period.
For maximum life and best performance, change the “lifetime” fluid in your vehicle’s filled-for-life or sealed transmission or differential at least once, but more often if your driving conditions fall under the severe designation.
Changing fluid in these units may tax one’s mechanical aptitude, but it can be done. You likely need to visit the dealer or a mechanic since special tools can be required. Some manufacturers also prescribe complicated procedures spelled out in a service manual for changing fluids.
Anyone who has changed gear lube before – whether on a “filled-for-life” differential or traditional unit – knows the hassle involved: a tough-to-reach fill hole, gear lube spilled everywhere and bloody knuckles.
Our SEVERE GEAR easy-pack offers the perfect solution. Compared to rigid conical bottles that waste a quarter of the gear lube or more, our easy-pack offers the dexterity to maneuver around vehicle components and the flexibility to install nearly every drop of gear lube. It eases the process of changing gear lube, saving you time and hassle.
To flush or not to flush. (One of our best sellers here in Sioux Falls)
It’s a question whose answer is obvious in the bathroom, but vigorously debated in the garage.
Let’s get right to the point. Is an engine flush good or bad?
Spend a few minutes perusing online forums and you’ll find a range of answers to this question, often involving a 1980s Trans-Am, Camaro or other car that someone thrashed on for years, parked in a pasture for a decade and now wants to revive with an engine flush.
Here’s what we’ll cover:
What is an engine flush?
How deposits and sludge form
Can engine sludge be removed?
Is an engine flush necessary?
Engine flush as part of maintenance
5 benefits of an engine flush
Engine flush products
Watch: How to do an engine flush (video)
What is an engine flush?
An engine flush is an aftermarket chemical additive designed to clean accumulated deposits, sludge and other gunk from your engine. You pour it into your engine’s oil-filler port and idle the engine for about 10-15 minutes. It mixes with the oil and circulates through the engine, helping dissolve sludge and clean deposits. Then, you drain the oil (along with much of the gunk, in theory), change the oil filter, add fresh oil and return to the business of driving.
How deposits and sludge form inside an engine
If it did its job, your engine’s performance will return to the heady days of its youth, when it delivered maximum power and efficiency. Over time, however, harmful deposits and sludge may have accumulated, causing power and performance loss.
The tiny openings in the oil pickup tube screen can easily plug with sludge, starving the engine of oil.
Deposits and sludge can form for several reasons, including…
Frequent short trips that don’t allow the oil to fully warm up and evaporate moisture
Ingestion of air-borne dirt
Fuel dilution
High heat breaking down the oil
As it settles, sludge can clog narrow oil passages or the screen on the oil pickup tube, restricting oil flow to vital parts, especially the upper valve train. Deposits can cause the rings to stick, reducing engine compression and horsepower.
Can engine sludge be removed?
Yes. The proper detergents in the correct concentration can dissolve engine sludge, deposits and varnish. Ideally, sludge won’t form at all; however, sometimes mechanical issues arise, such as a leaking head gasket, and the formation of sludge occurs. If sludge does form, the oil’s detergents help dissolve and disperse sludge to clean the engine.
This is more challenging than it sounds. For starters, the oil must perform several functions, not just help prevent engine sludge. For that reason, oils contain a limited concentration of detergents (compared to an engine flush product) to ensure room in the formulation for other additives that protect against wear, fight oxidation, combat rust and more.
An engine flush product, on the other hand, is designed solely to clean. AMSOIL Engine and Transmission Flush, for example, contains nothing but potent detergents, making it a more effective cleaner than motor oil. Plus, it cleans at the molecular level, ensuring deposits are dissolved and properly exit the engine with the oil when it’s drained. This is important since some motorists fear that an engine flush will free large chunks and cause an avalanche of debris to clog passages inside the engine. AMSOIL Engine and Transmission Flush guards against this scenario.
Is an engine flush necessary?
A good engine flush can help loosen deposits and dissolve sludge, returning your engine to like-new condition. However, in old engines with high miles, sludge may be the only barrier keeping oil from seeping through worn or cracked seals. Removing the sludge exposes the seals for what they really are – junk. Soon, your engine begins leaking oil, and you’re mind instantly associates the engine flush product with an oil leak.
In reality, the seals were already bad; the flush simply revealed their true condition.
If you suspect your vehicle falls into this camp, leave well enough alone and skip the engine flush. It’s probably not worth trying to revive an engine in such poor condition without first fixing the bad seals or other defects.
In effect, you’re choosing your problem: either sludge and deposits robbing performance or, if you clean the engine, the seals showing their true condition.
An engine flush is part of a good maintenance regimen
But that’s not to say an engine flush is never a good idea. In fact, it’s often the first step in helping restore a neglected vehicle to top-notch performance. And, often when you buy a used vehicle, that’s what you’re getting – a vehicle whose owner found antiquing on Saturday afternoon more enjoyable than changing oil or dropping the transmission pan. Consequently, your “pre-owned” ride, while not complete junk, may boast a sketchy maintenance record.
In these cases, a potent, detergent-based flush can help prepare the engine for new oil, loosening sticky valves or rings and helping remove harmful sludge. While not a required step when switching to AMSOIL synthetic motor oil, we do recommend flushing your engine if you want to give your vehicle a fresh start.
5 benefits of an engine flush
1. Prepares your engine for new oil
An engine flush helps loosen sticky valves or rings and remove harmful sludge and other contaminants. By cleaning the engine prior to installing fresh oil, you ensure the new oil functions as intended and delivers maximum protection. The oil won’t last as long or protect as well if it must contend with sludge and deposits from the previous oil.
By the way, we don’t require use of AMSOIL Engine and Transmission Flush before switching to AMSOIL synthetic motor oil, but we recommend flushing your engine if you want to give it a fresh start.
2. Helps increase fuel efficiency
Contaminants circulating throughout the engine can lead to oil breakdown and increased viscosity – and higher-viscosity oil requires more energy to circulate throughout the engine. Sludge and deposits on engine parts can also increase resistance, which wastes fuel to overcome. Cleaning the engine helps ensure parts move efficiently, maximizing fuel economy.
3. Helps reduce emissions
If deposits in the piston-ring lands cause the rings to stick, oil can migrate into the combustion chamber, where it burns. This not only leads to harmful deposits, it also increases exhaust emissions as the burned oil exits the tailpipe. A good engine flush helps free stuck rings and reduce oil consumption, in turn reducing emissions.
4. Helps reduce heat
Excessive heat is bad for your engine and the oil. Extreme heat reduces engine efficiency while increasing the rate at which the oil oxidizes (chemically breaks down). Sludge and deposits act as insulators that prevent the engine from dissipating heat as designed. Flushing your engine helps ensure it manages heat properly for optimum efficiency and oil life.
5. Convenience
This might not apply to every engine flush, but it applies to AMSOIL Engine and Transmission Flush. It delivers results after just one application. And it only takes 10-15 minutes to use. Plus, you can safely use it in gas or diesel engines and automatic transmissions. While some solvent-based flush products require a cumbersome disposal process, AMSOIL Engine and Transmission Flush uses a detergent-based formulation. As such, you can dispose of it easily with waste oil.
Cylinder head pre-cleanup. Note the sludge around the valve springs and push rod openings.
Post-cleanup with AMSOIL Engine and Transmission Flush, the cylinder head is noticeably cleaner.
Engine Flush Products: I use AMSOIL Engine and Transmission Flush
For the record, I’ve used AMSOIL Engine and Transmission Flush on three different pre-owned vehicles in my time, and it’s worked great. One of them, a 1999 Honda CR-V, accumulated more than 220,000 miles before rust forced me to replace it. Another, an Oldsmobile Intrigue, ran great until a computer problem forced me to trade it off…for the CR-V. The third ran great, but I sold it off after it, too, rusted out.
In sum, flush your engine if you want to give your vehicle a new lease on life. AMSOIL Engine and Transmission Flush, as the name indicates, also works great for cleaning automatic transmissions. Check out this post to determine if a transmission flush or pan drop is better for you. But if you have any reservations about disturbing sludge or deposits that may be holding your old, high-mileage engine together, consider skipping it. It’s up to you.
How to do an engine flush
If you are looking for the best way to flush your engine this weekend, here’s a quick video that will walk you through the process, courtesy of MyJeepStory.
It depends on what you want to accomplish. But, first of all, check your owner’s manual to see if your vehicle manufacturer recommends one instead of the other.
If you want to ensure removal of nearly all the old transmission fluid, then have your transmission flushed.
The benefits are self-evident: all the old, dirty fluid is replaced with fresh, high-quality fluid. (And, as you can see in the image, new transmission fluid is preferable to old fluid). As a result, your transmission should run cooler and receive maximum protection against wear to clutches, gears and bearings. It should also shift consistently and crisply since the new fluid will provide the correct frictional properties (old fluid loses its frictional properties over time).
Not only that, but performing a flush helps clean the transmission. Sludge and other contaminants can accumulate in the fluid due to extreme heat breaking down the fluid. These contaminants circulate throughout the transmission before lodging in the filter. Before the filter can safely capture the contaminants, however, they can lodge in the narrow fluid passages inside the valve body, leading to poor shift quality.
The narrow fluid passages in the transmission valve body can easily clog with debris, reducing shift quality.
Performing a flush also allows you to use a flush additive to help clean the transmission and more effectively remove accumulated sludge and other contaminants.
Any downsides?
Potentially.
For one, it’s more expensive. And some people warn against performing a flush on a transmission using old, dirty fluid. The flushing procedure may direct the fluid in the opposite direction of normal flow, which may increase the risk of dislodging debris and causing it to settle somewhere it shouldn’t. Since the way each shop performs a flushing procedure varies, you can’t know for certain.
What is a transmission flushing machine?
A typical flushing machine uses hoses that connect into the transmission cooling lines. It drains the old fluid and holds it inside the machine while replenishing the transmission with new fluid. Unlike a simple pan drop, a flushing machine removes just about all the old fluid, including the fluid inside the torque converter.
Since the procedure uses new fluid to perform the flush, it requires several quarts of new fluid beyond the transmission’s final capacity. Those extra quarts are where most of the added cost lies.
If you have reservations about a flush, go with a pan-drop instead. While it reduces the risk associated with flushing old, dirty fluid through the transmission, a pan-drop also has downsides.
Removes only about a third of the fluid
Can be a mess
Can be a pain on some vehicles
I can tell you from experience that a pan-drop can be a bigger job than you think. You may have to remove plastic splash guards or metal skid plates to access the transmission pan. In case you haven’t been under your vehicle in a while, plan on encountering rusted, stuck bolts if you drive in wet, snowy conditions. Don’t be surprised if you crack a splash guard in one or two places as you try to remove/reinstall it.
Tips for performing a pan-drop:
Have a large catch pan handy. Otherwise, once you loosen the pan bolts, fluid is going to ooze from the pan/transmission interface and end up all over the floor.
If you’re crafty, you can back out the pan bolts in one corner further than the surrounding bolts, effectively tilting the pan so the fluid drains from a single corner instead of overflowing the entire pan. This reduces mess quite a bit.
Wear safety glasses and gloves.
Don’t forget the new filter and pan gasket.
It’s a good idea to know the torque specs on the pan bolts and use a torque wrench to reinstall them. Otherwise you risk overtightening and ruining the gasket.
You might get lucky, though
Some vehicle manufacturers install a drain plug on the transmission, similar to a motor oil drain plug. This allows you to easily and cleanly drain some fluid from the transmission minus the hassle of removing the pan. Again, though, you only get a third to half the fluid out.
You can then drive the vehicle for a while, then drain the fluid and change it again. Do this 2-3 times and you’ll remove nearly all the old fluid and perform a sort of poor-man’s transmission fluid flush.
Bottom line: Visit a pro and have the transmission flushed for best results and least hassle (unless your vehicle manufacturer specifically warns against it in the owner’s manual). But, if you have reservations about dislodging debris due to old, dirty fluid, a series of pan drops works just as well.
