Downshifting a CVT.

[bubshoe]

I honestly use it when braking for a turn or just to slow down faster. Anyone else do the same?

 

Is there any real hazard to doing this? Im not shooting the rpms above 3k. Just helping little nudges.

 

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[waldguy]

I've done it from time to time. Hardly ever though.

 

Just that brakes are a lot cheaper to replace than CVTs - after a hundred thousand miles of continually doing this, it will result in higher stress on CVT components.

[Perscitus]

Nothing wrong here OP, continue doing what you're doing.

 

Just don't throw it in 'Neutral' while coasting or cruising

or 'Reverse' while at speed and you'll be fine.

[Ronin3.6R]

I use it fairly frequently to slow down at say a light that changes yellow on me etc. Seems to work great for this.

[Woony1990]

Debatable topic, but the physics never change. Braking(slowing) of any object by friction generates heat. And life of any component degrades after being applied with enough heat and friction. Brake pads are made to be replaced because the surface needs to be refreshed and cut by micro level to keep its peak performance. Even though, transmissions are built to last quite long time under normal operation, no one can determine exactly what is "normal operation" but the physics tells you that it will definitely shorten the life span.

 

So, if I were you, I wouldn't make it a habit. Engine braking is absolutely valid when you are going down long hill like mountains to avoid over heating the brakes which makes them to degrade much faster. But like it's been said above, brake pads are much cheaper to replace. I just don't see enough reason to use engine braking on the street. Transmission break down is one of the things that I absolutely want to avoid dealing with. It will cost a lot to fix it. In fact, most transmission WILL eventually fail at some point whether you like it or not; it's just matter of time. By engine braking, you might be expediting the consequence.

[Ronin3.6R]

I can't argue your logic, but I would sure hope the CVT can take "braking" at the level we are talking about for goodness sake. If not and it is certainly doing damage then I would cease I guess.

[upstater]

Being obsessive/compulsive about manually downshifting your CVT transmission to routinely slow down your car is about as smart as resting your hand on a manual gearshift or riding your brakes all the time.

 

From a cost perspective, a CVT rebuild (I think they still just replace it with a new transmission instead of rebuilding it?) is only ~$13,000.

 

Since Subaru extended the CVT warranty, you probably won't eat that cost if you trade before 100k or if it fails during the new extended warranty.

 

Most likely it will be fine through that warranty period, and just fail sooner in the later life of the car, due to the continual/minimal abuse.

 

But that is the glory of having the freedom to do dumb things, that you know are wrong (or at least are told are not good habits), you can keep on doing it as much as you wish because it is your car.

[08SpecB_DE]

I'd like to see the study where resting your hand on the shifter causes problems. I usually have my hand on my thigh but in slow stop and go traffic, i will stay on the shifter.

[YeuEmMaiMai]

you can use the CVT to engine brake but I would only do it in situations were it is needed like going down a long grade

[upstater]

I'd like to see the study where resting your hand on the shifter causes problems. I usually have my hand on my thigh but in slow stop and go traffic, i will stay on the shifter.

 

 

 

It's mostly just those danged car 'experts' who recommend against it, I'll just guess in advance that no source is going to be scientifically adequate to convince you not to routinely do that.

[YeuEmMaiMai]

I'd like to see the study where resting your hand on the shifter causes problems. I usually have my hand on my thigh but in slow stop and go traffic, i will stay on the shifter.

 

1. it removes your hand from the wheel and in an emergency situation that is not a good place to be in

2. on some manuals it can cause premature wear of parts.

[jnrhoads1]

I have also read where excessive engine braking can cause excess oil consumption. I know these cars generally do consume oil and I also use the engine braking quite a bit as I live in a mountainous area. I also have to add a quart of oil about every 1,300 miles.

[ehsnils]

I've done it from time to time. Hardly ever though.

 

Just that brakes are a lot cheaper to replace than CVTs - after a hundred thousand miles of continually doing this, it will result in higher stress on CVT components.

The actual torque transfer is a lot lower than what you get when you give it a full throttle and the gearbox is designed for this in mind so it's not really anything to be concerned about.

 

 

The software will also protect against any unsafe dowshifts.

 

 

When driving down in hills/mountains it's the preferred way to keep the speed and saves the brakes from overheating so that they are fresh when/if you need them.

[Woony1990]

I can't argue your logic, but I would sure hope the CVT can take "braking" at the level we are talking about for goodness sake. If not and it is certainly doing damage then I would cease I guess.

 

I don't think anyone will say it's going to damage the transmission. Better explanation would be that you will wear transmission little bit faster. If you think about it, engine braking at certain RPM would be the same load on transmission and engine as if you are to accelerate at the same RPM. So unless you are going crazy, you are not going to do any DAMAGE per say, but you are indeed putting more strain to the transmission by decelerating car by engine braking and not brakes.

 

My logic is that I want to avoid any unnecessary strain on the transmission. Everybody want their tires and brakes to last as much as possible, but why would you pay the price with more strain on the transmission when transmission is much more expensive? Transmissions wear out under normal operation, otherwise, no one would visit transmission shop unless you are a race driver.(Okay, drivers who really believe that the transmission oils last lifetime like manual says are exceptions..) They wear just like brake pads do, it's just that they last quite more than brakes pads with proper maintenance. So I just choose to save transmission and use brakes whenever....braking.

 

If your car is leased and you are not keeping the car more than 5 years.. why not?? do engine braking, go full throttle whenever possible, and do what ever you want to do. car will be just fine. but if you want to keep your car for long time without trouble.. I would be very gentle with our transmission and just don't take any chances.

[Ronin3.6R]

I guess I have more faith in Subaru then to think that down shifting is going to cost me $13K. But anyway, my "record" for keeping a car is 5 years. I like upgrading. I have even looked at upgrading now but the damn Legacy does too many things well. It's not the fastest, most luxurious etc. but it checks a lot of boxes for the money. This may be another record!

[08SpecB_DE]

 

It's mostly just those danged car 'experts' who recommend against it, I'll just guess in advance that no source is going to be scientifically adequate to convince you not to routinely do that.

 

Funny the expert said it was okay when i do it so i guess Im in the clear. I drive with 1 hand and often only a couple fingers so 2 hands on the wheel does not apply to my driving style. All im saying is i have never seen it cause problems and know people who drive like that and have never reported an issue.

[Eugene Onegin]

The only time I down shift is when I'm going up hill ,I don't like to labor the engine .

[ArmyVetMP]

I have over 207k on my 2010 Legacy with CVT. I use the shift paddles to downshift fairly often and have yet to have any issues with my car. Currently, I am using it more often than I usually do simply because I have a badly warped rotor on my Front Drivers side brakes, and currently don't have the time to replace them. So I use the CVT to slow the car to help reduce the vibration I get from the warped rotor (the brakes still work as they should, the vibration is just annoying, especially at highway speed).

[fastcar123]

Nothing wrong here OP, continue doing what you're doing.

 

Just don't throw it in 'Neutral' while coasting or cruising

or 'Reverse' while at speed and you'll be fine.

 

Pardon my going off topic here but what is the problem with neutral while coasting?

I do this from time to time and didn't realize it was a bad thing to do.

[Perscitus]

http://lmgtfy.com/?q=CVT+AT+problem+with+neutral+while+coasting

[upstater]

the fun thing is we can tell you why coasting in neutral with a CVT is bad, or why driving around in a car with a manual transmission while resting your hand on the gear shift can be problematic, or obsessively downshifting to engine brake vs using your brakes to slow down is increasing wear and tear on your transmission...

 

 

but you will do it anyway, so why ask questions you don't like the answers to?

[ehsnils]

Pardon my going off topic here but what is the problem with neutral while coasting?

I do this from time to time and didn't realize it was a bad thing to do.

On a manual gearbox - not so much unless you have an immediate need to use engine power.

 

 

On an automatic gearbox then it may put a lot of things into rotation that don't get proper oil feed and also it may have selected an improper gear ratio causing parts inside to exceed the rpms they are designed for. So neutral on an auto (No matter if it's stepped or CVT) is more risky than doing the engine braking.

 

 

 

The torque imposed when doing an engine braking is lower than when accelerating. Just make a test yourself and see - you get a lot more acceleration when you push the throttle than retarding when you downshift.

[YeuEmMaiMai]

the biggest reason not to but any transmission in neutral while coasting is that you will actually be burning more fuel. All modern cars use a fuel cut strategy when you take your foot off the gas and let the car coast. the ECM will immediately cut fuel to the injectors and let the transmission turn the engine mechanically...down to about 1200rpm (varies by car)before turning the injectors back on...

 

also most all automatics will prevent over revving when downshifting as they are electronically controlled and will prevent downshifting if the resulting gear will over speed the engine mechanically... been that way for a few decades now....