CVT Wear Rate

[supton]

Excluding any problematic CVT's...

My understanding for conventional slushboxes is that, every time they shift, some friction surface takes some wear. Just like in a conventional manual transmission (albeit that any worn material floats around in the fluid and other factors).

I only have a vague understanding of CVT's, but it seems like they don't have friction surfaces. Or, they have surfaces which wear but are not lined with friction material.

So, my question is, would a CVT basically have a fixed wear rate? It could ramp up and down the "ratios" (or gears or whatever you want to call it) constantly yet wear out at the same rate as if it was put into a fixed ratio (like say top gear, cruising on the highway).

 

[SwampSurvivor]

The two cones and the metal belt are the only things that could really wear. The mechanism that actuates the cones could probably wear out as well.

Figure out how to keep them from snapping the belt and I'm sure they would last quite a while.

 

[supton]

I know I get annoyed with a transmission that constantly shifting--but part of that comes from the fear of wear. Makes me wonder if a CVT can hunt up and down all it wants, and it would matter not a thing to longevity.

 

[4wheeldog]

Theoretically, CVTs don't slip. At least, the modern ones are designed not to. So, yes, there is wear....But not in the same way that conventional AT clutches wear. As already stated, the belt/chain and conical surfaces will wear, but very little, since they are not slipping.

The only "Clutch" in a CVT is the torque convertor, which locks up early and stays locked. (Though I suspect that they do not lock until the transmission reaches some minimum temperature. Mine acts looser, during the warm up, while driving.)

In fact, the running up and down in ratios seem like it would keep any notches from developing in the conical surfaces. Running in a constant ratio would have the opposite effect.

 

[Shannow]

Technically yes they do...had to maintain a couple of old "PIV" brand industrial CVTs a while ago, and while they were CVT, they were a tuning device to get exactly the correct speed on an application...therefore set to a specific speed, and run like that for a decade.

They developed (surprise) a step in the cones, that meant that they didn't want to operate either side of the step, were OK a long way from the step, and lost their ratio at the step.

An automotie CVT will undoubtedly spread the wear across the whole face, not just groove up one location.

 

[Ram01]

Trust in honda CVT they are build for the long haul. Nissan's cvt kinda of drop the ball on there's but is getting better

 

[wag123]

Originally Posted By: Ram01
Trust in honda CVT they are build for the long haul. Nissan's cvt kinda of drop the ball on there's but is getting better

What?
Nissan has earned a very good reputation on most of their automatics over the years. Their early CVTs had some "teething pains", and they have had a couple of limited production/assembly problems along the way (for which they have given their customers warranty extensions), but it appears that they have worked the problems out.
Honda is the company that has earned a bad reputation on some of their automatics. In particular, the automatics that Honda used on their V/6s prior to 2006 were AWFUL, but they have also had many other problems (on-and-off) over the years going all the way back to the very first Hondamatics that they produced. Based upon this, IMHO Honda's first CVT automatics should NOT be trusted.

But, like them or not, CVT automatics are here to stay.

 

[ffhdriver]

All hybrid car CVTs I know about have no belt and cones, only gears. Haven't seen reports of repair problems on them.

 

[thrace]

Plenty of Honda Civic Hybrid transmission problems. It's a CVT.

It's the Prius that has very few transmission problems.

Just from a few clicks found these Honda Civic Hybrid problems:

"2003 Honda Civic Hybrid in 2005. Clean record.
At 44,000 miles transmission went dead per my Honda dealer service department. Replacement $3,500 for refurbished one (told they do not make original ones which raises questions re quality). No advance indication of potential failure."

"I have a 2003 that the internal computer came up w/ a code 1890, "slippage between shifts." Dealership told me that I needed a new transmission at 80,xxx miles,"

"My wifes 05 HCH -w- CVT did it at 35k miles all dealer maintance. D doesn't light up. car started jumping even if you try to put in park. Dealer replaced tranny; 2 weeks in the shop."

"My car has 116,xxx miles on it and the auto trans is already slipping on my 03 Honda Civic Hybrid."

http://forums.edmunds.com/discussion/4930/honda/civic/honda-civic-hybrid-transmission-problems
===================

 

[ffhdriver]

Originally Posted By: thrace
Plenty of Honda Civic Hybrid transmission problems. It's a CVT.

It's the Prius that has very few transmission problems.

Just from a few clicks found these Honda Civic Hybrid problems:

"2003 Honda Civic Hybrid in 2005. Clean record.
At 44,000 miles transmission went dead per my Honda dealer service department. Replacement $3,500 for refurbished one (told they do not make original ones which raises questions re quality). No advance indication of potential failure."

"I have a 2003 that the internal computer came up w/ a code 1890, "slippage between shifts." Dealership told me that I needed a new transmission at 80,xxx miles,"

"My wifes 05 HCH -w- CVT did it at 35k miles all dealer maintance. D doesn't light up. car started jumping even if you try to put in park. Dealer replaced tranny; 2 weeks in the shop."

"My car has 116,xxx miles on it and the auto trans is already slipping on my 03 Honda Civic Hybrid."

http://forums.edmunds.com/discussion/4930/honda/civic/honda-civic-hybrid-transmission-problems. Wow, hadn't seen that before. Honda has had several problems over the years with non-hybrid transmissions so I'm not surprised about their hybrids. Wonder how Honda's hybrid transmissions differ from Toyota's? ===================

 

[supton]

The Prius doesn't have a transmission, at least not conventional. I have not looked into one to make sure there isn't a clutch of some sort, but last I knew it was nothing more than a glorified differential--it sums the two outputs together to drive the vehicle. Electric motor plus gas motor. In reverse the electric motor just spins backwards.

As such, there is practically nothing to wear out.

 

[ffhdriver]

I GOOGLED the transmission after trace's post and it looks like 2003 wasn't a good year. Maybe 2014 is better.

 

[itguy08]

Originally Posted By: Ram01
Trust in honda CVT they are build for the long haul. Nissan's cvt kinda of drop the ball on there's but is getting better


I wouldn't trust an Auto anything from Honda. Their junk is the same as other junk just wrapped with an "aura" of superiority.

 

[Cujet]

Originally Posted By: itguy08
I wouldn't trust an Auto anything from Honda. Their junk is the same as other junk just wrapped with an "aura" of superiority.


The real world data from "True Delta dot com" does not back up your statement. In fact, Honda's are stunningly reliable, as reported by actual long term owners.

The reality is that Honda and Toyota build cars that match each other in long term reliability. All other manufacturers fall short of the Honda/Toyota numbers. A comparison between 1998 thru 2014 Accord's and Passat's is an eye opener! http://www.truedelta.com/Honda-Accord/reliability-108/vs-Passat-282

Note: some competitive makes and models, by year, are 5 to 10 times more likely to have a reliability issue as compared to a Honda Accord.

Lets talk facts and not feelings. Real world data is important.

 

[SteveSRT8]

The only sad thing here is anyone imagining there is no wear. That's simply ludicrous, and no one with any real automotive repair experience would ever assert that moving parts in rubbing contact never wear.

All you reliability folks are just arguing over how long it takes to wear it out.

Since I just sold an American made van with over 1/2 million miles on it that ran excellent and passed an aircraft pilot's inspection (he bought it) I think that statistics are wonderful when applied to a GROUP of cars.

But they mean much less to an individual unit...

 

[buster]

Subaru CVT is bulletproof.

 

[147_Grain]

Originally Posted By: buster
Subaru CVT is bulletproof.

+1

 

[supton]

Originally Posted By: SteveSRT8
The only sad thing here is anyone imagining there is no wear. That's simply ludicrous, and no one with any real automotive repair experience would ever assert that moving parts in rubbing contact never wear.

All you reliability folks are just arguing over how long it takes to wear it out.

Since I just sold an American made van with over 1/2 million miles on it that ran excellent and passed an aircraft pilot's inspection (he bought it) I think that statistics are wonderful when applied to a GROUP of cars.

But they mean much less to an individual unit...


I was curious about how they wore differently than conventional autos. Shannow's comment about how it's good for them to hunt a bit is interesting I think.

IMO CVT's kinda turn things on their head. I've long driven stickshift, and with motors that were relatively torquey. No need to shift while on the highway--just a bit more throttle to maintain speed. Jumping into my truck and now I have to watch my speed and throttle, as I'm trying to maximize top gear usage, so as to minimize fuel usage. Some day I will have to try a CVT and see what it feels like. I'm guessing it's one of those things I'd have to simply adapt to.

 

[itguy08]

Originally Posted By: Cujet

The real world data from "True Delta dot com" does not back up your statement. In fact, Honda's are stunningly reliable, as reported by actual long term owners.


I wouldn't trust Truedelta to wipe my butt. Been a while since I've been to the site but was not impressed in the least.

The owner spams pretty much all forums related to cars to get people to sign up. And then there is the "trip to the shop" thing that is basically useless. A trip to the shop for a squeak or rattle is a lot different than a trip to the shop for a new engine or transmission!

I'd rather have a car that goes in 10 times to fix a bunch of little things than have a new engine or transmission. Truedelta attempts to assign all repairs an equal rating when they are not!!!

Quote:
The reality is that Honda and Toyota build cars that match each other in long term reliability. All other manufacturers fall short of the Honda/Toyota numbers. A comparison between 1998 thru 2014 Accord's and Passat's is an eye opener! http://www.truedelta.com/Honda-Accord/reliability-108/vs-Passat-282


1st of all - VW's reliability is typically less than the industry average so that's not exactly a good comparison.

2nd - those owners tend to gloss over many issues because they have been told that they are the best. I find it hilarious that an owner of a Honda from 2000-2008 with a bum 5 speed auto prior to 100k will replace it and sing how "reliable" their Honda is? Really? You kidding me? The "junk" CD4E in the wife's Escape is 145k and still original! Or those that have an oil burning Honda V6 say how great it is! How many had Sludgy Toyotas or rusty framed Tundras that still thought they were the best? (I'd bet a lot)

I know someone that loves Hondas. Thing is he leases them - and ever 3/36k or whatever he gets a new one! Heck, even the lowest rated car would be fine in that short period of time.

Quote:
Lets talk facts and not feelings. Real world data is important.

Within every owner reported sampling there will be bias. If you are constantly told something is "the best", you will gloss over any issues. After all, if it's the best and blows trannys, how bad is the worst?

The best "fact" would be warranty repairs or parts sales data. Sadly warranty repairs would never been made public. Since people don't generally buy parts until something is wrong that would be a good indicator of long term reliability.

Sorry, I'm not buying the theory that Honda/Toyota is leaps and bounds ahead of everyone else. It's been bunk for a LONG time now.

 

[jorton]

I wasn't sure if I liked the cvt(2) in my Jeep Patriot until last week when I used my brothers Dodge Ram with 8 speed auto for 5 days. I would say these two designs are 180 out, and it's a pleasure to be back behind the wheel of my Patriot.