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Possible to replace the CVT belt?

48K views 17 replies 11 participants last post by  umie66 
#1 ·
My 2011 CVT has just under 100K miles on it and during a drive from Los Angeles to San Francisco up the 5 freeway I noticed that after around 150 miles of driving at 80MPH the car required significantly more rpms to hold speed than it did during the first part of the drive. It got so bad that by the time I was near SF the car was struggling to stay above 72mph at the same rpms. The result was a total trip mpg of around 33mpg. I was expecting a bit less than average as 80mph requires more gas but I fear the higher and higher rpms didn't help.

I feel like the need for higher and higher rpms to keep the same speed is a result of transmission slippage, and in this case, possibly due to the belt stretching after more and more constant use. Day to day driving is still fine now but I have encountered this problem before on that long drive, just never this bad. I feel like once the car cools after the trip then the belt returns (somewhat) to its tighter form.

Has anyone else experienced this? Also, does anyone know if it's possible to replace just the belt or would it be a whole new tranny? Maybe theres another solution too? I know I'm due for a CVT fluid change, maybe that's my issue? Just looking for some feedback from those with experience, thanks.
 
#3 ·
It's certainly possible, but you never know what a dealership will do. I had the oil pan and the oil filter on my CVT replaced after a rock punched a hole through them and the car's running fine 15k miles later. Everyone on the forum was recommending a full transmission replacement, but the Honda guys seemed to know what they were doing by just replacing those two parts.

In summation...idk :dunno:



The CVT belt/pulley assembly is supposed to look something like this. No teeth. Just the two axles and the belt. What boggles me is that I can't figure out how there isn't more slipping that we actually feel.

 
#4 ·
Thanks for that awesome image. I've been looking for something like that for a while now.

Looking at that picture I have to imagine there is some sort of rubber on the underside of that, but looking online most belts are metal on both sides with a metal belt/band in the middle, no rubber anywhere.

I wonder if it's not my belt expanding with use, but something else, like maybe the actuator that squeezes the two cones together wears out after a while. Or maybe the clutch plates slip with high heat and lots of lubrication? I'm going to do the drive again on Sunday and will report back with specific rpm/speed details for a better analysis.
 
#5 ·
Yeah, I would get a transmission expert, preferably Honda trained, to diagnose it.
Could be belt, I suppose, or could be clutch(es), or who knows what else.
At 100K miles, how many times have you (and when was the last time you) changed the CVT fluid? I know you said it was "due", but is that because you just thought of it, or are you keeping to the recommended schedule or better?

2 hours at 80 shouldn't really kill a transmission. Especially at highway speed (which is probably pretty constant, unless you have lots of hills and traffic tie-ups - sorry, but I don't know the highway in question).

Also, if your brakes are dragging even slightly, after 150 miles at that speed they would definitely heat up and drag more (meaning that the drive train would have to work a lot harder to keep speed). That might explain why city driving is no issue. Just a thought.

One or two CVT failures in thousands of cars, and we all jump on the "rebuild" band wagon. I'm not so cure that is warranted. Be careful about posting in panic. If it gets diagnosed as a tranny fault, then let us know. But I'm sceptical.

Good luck with it, in any event.
 
#6 ·
Well, let me throw this one in here too (this is from a Nissan tho). This is a cross section of the belt. I believe the yellow part is some sort of plastic or composite material that holds all those little metal pieces in line. I could see the plastic being prone to plastic deformation after x amount of miles. I can also see how the metal pieces might grind down too :blink:

 
#7 ·
CVT belts are not supposed to slip , they are under extreme pressure to prevent that . The belt never makes contact with the pulley . The oil is what provides friction to move the belt . That's why it's critical to have not only clean fluid but the correct OEM fluid and not some generic type .
 
#9 ·
Last fluid change at 66k and you're just under 100k now...? I reckon that's it. My started acting out under high stress (sport mode spirited driving) around 20k, and after a fluid change it's been fine.
 
#13 · (Edited)
On All-Data (perk of being an automotive technician) the maintenance interval for the CVT fluid is every 30K miles, both for normal and severe conditions. It does mention that Honda just recommends changing it according to the maintenance minder. The 30K interval is like an average based on the maintenance minder possible minimum and recommended maximum.

I would recommend changing the CVT fluid again since it seams you have a degradation of performance on long drives and stress. Best preventive for problems later is frequent maintenance!

And I would second a valve lash check/adjustment also, this does require new upper intake manifold gaskets, throttle body gasket and valve cover gasket.
 
#14 ·
knowing nothing about cvt my input is pretty useless but op have you considered the fact that on a long road trip to nor cal youre going to come into contact with all sorts of variances in wind/air and weather conditions? denser/thinner air types will affect AFRs and if youre tryna maintain that speed (which is way too high to maintain any sort of good mpg, if thats a concern) your car will have to compete to keep up. even in a manual transmission this is noticeable during a trip to vegas lets say (im only referencing this because i know for a fact that i experienced a similar case in a different car with a different transmission [07 si] during which time mpg was not a concern). anyways how many elevation changes occur on the way to frisco? which route did u take? so many things will affect the vehicles performance. id say compare your car to what your used to doing at your baeline driving behavior in los angeles. then, if u see strange behavior from the car then something is wrong. if not, well then your car has not done wrong, it simply was adjusting to the change of environment in which u drove it. good luck i hope your car is ok. next time get a 6mt :thumbsup: haha jk
 
#15 ·
I wish I could've gotten a 6mt but new cars are such a rip off and most used ones in my area were CVT's. Combine that with the fact that mine was only $10k with service records and a dealer warranty and my decision was pretty much made for me.

The drive is relatively flat in the middle, though there are some hills near SF and LA. The symptoms occurred well apart from any hills but it's possible wind could have been an issue, but I don't have a wind gauge on my car so it's hard to say... Like I said, I'm driving back down to LA on Sunday so I'll report back with specific rpm/mph details then.
 
#16 ·
Just thought I would update all those who were trying to help with this.

I did the drive last week and found that the issue I described was no longer there. However, the drive was not really comparable to the first one as this time there was a strong tail wind, the car just had a oil change, and my skid plate/shield under the car fell off which may have affected aerodynamics or cooling of the tranny.

Anyway, in ECO mode on level grade at 2500rpm the car did 77mph and at 2600rpm it did 80mph, for the entire drive, so no "stretching" or struggling like last time, which is great but inconclusive as I am sure it was acting funny during the first drive.

I also got the CVT fluid replaced at a local Honda dealer the other day. He said they had to flush and "burnish" the transmission twice (that's a lot) to finally get the fluid to come out clean, which means that dirty fluid may have been making it act up. Thanks for the help guys.
 
#17 ·
Just thought I would update all those who were trying to help with this.

...
I also got the CVT fluid replaced at a local Honda dealer the other day. He said they had to flush and "burnish" the transmission twice (that's a lot) to finally get the fluid to come out clean, which means that dirty fluid may have been making it act up. Thanks for the help guys.
Glad that it worked well for you this time.

And your last comment is a good wake-up call to the rest of us, to not let it go too far before changing. I'd rather blow a few bucks doing it a little too frequently, than be stuck on the side of the road with an impending repair bill that might be 3/4 of what the car is worth!

I think that the CVT is a pretty solid unit. Quirky, for sure, but mechanically quite sound. It is new technology to most of us, and I would certainly prefer an MT or conventional automatic. So it isn't surprising that one person with issues suddenly make us all fear for our cars. Glad that you were able to restore some sense of calm - not only to your own life, but to the universe as well ("universe", as in "this forum").
:D
 
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