Anyone with automotive CVT transmission experience - PeachParts Mercedes-Benz Forum

engatwork · #1 10-17-2012, 08:16 PM

Curious to find out what other folks experience is with this design. Seems alot of cars are starting to come with them. Saw one the other day in a Nissan Murano that the fluid had never been changed in the transmission and it was worn out at ~210k miles. When I did a little research it seems that they don't get rebuilt but replaced. They are quite pricey too.

Benz Fan · #2 10-17-2012, 08:38 PM

Is that a typo? 210,000 miles?

engatwork · #3 10-17-2012, 08:41 PM

no typo

engatwork · #4 10-17-2012, 08:43 PM

Seems on that application Nissan "test" the fluid to determine it's life. From what I read it says that they never recommend changing it.

Txjake · #5 10-17-2012, 10:32 PM

sounds like a Jag I had. "Lifetime" fluid and no conventional way to check it. ZF autoboxes aren't cheap either

t walgamuth · #6 10-17-2012, 10:41 PM

I got to liking it when the Mrs had the insight. I suspect in a lighter vehicle it would last a lot longer. I don't see how changing the fluid would not be a good thing.

The action of the tranny is weird at first but very rational in its performance.

TylerH860 · #7 10-17-2012, 11:09 PM

My only experience is not touching them with a 10 foot pole.

Zulfiqar · #8 10-17-2012, 11:10 PM

I have seen a Honda CVT being rebuilt and I was assisting it. Its a belt drive but with no torque converter, instead theres a heavy flywheel with rotational springs as input and one clutch pack that allows the transmission to engage and slips while the car is stationary. It also allows a reverse.

Its notorious for slipping at high mileage - like 60,000 miles - and the CVT fluid gets in the range of 250F hot under load, not tow or anything just brisk acceleration from a 1.5 litre 4 cyl pulling a small car.

I have seen their belt assembly break too, it disintegrates into a thousand staple shaped pieces.

my wife drives a nissan altima 4 cyl with cvt - nissan say that the fluid never needs changing, dont believe it - im near 60K and have changed it myself, the drive improved quite a lot, previously it would have small jerks while accelerating gently from low speed - and still the dealer said its fine its supposed to do that - I told him that I have a 1995 mercedes benz with a fully hydraulic ancient transmission and it does have slight jerks or any sort of jerk while shifting - The service manager hates me I believe - nearly all of the times Ive been there with my car Im always wrong for complaining and comparing it to my old MB working

Skippy · #9 10-18-2012, 07:08 AM

I had the misfortune of having a Dodge Caliber rental with the CVT once. The concept seems sound but the execution was very flawed. In any type of hard driving, the ratio changes were several seconds behind.

t walgamuth · #10 10-18-2012, 07:13 AM

In the Insight I found kickdown to be instantanious and very effective.

engatwork · #11 10-18-2012, 07:54 AM

Reason I asked is because it seems that the next generation Accord is going to be using one.

I think they used the four wheelers and utility vehicles to sort em out.

Air&Road · #12 10-18-2012, 07:57 AM

Quote:

Originally Posted by TylerH860

My only experience is not touching them with a 10 foot pole.

You have good mechanical instincts!

engatwork · #13 10-18-2012, 07:59 AM

That is what I'm thinking too. Reading up on the Nissan says to just replace it when it goes out. From what I could find it was over $5k

?

Air&Road · #14 10-18-2012, 08:06 AM

Quote:

Originally Posted by engatwork

Curious to find out what other folks experience is with this design. Seems alot of cars are starting to come with them. Saw one the other day in a Nissan Murano that the fluid had never been changed in the transmission and it was worn out at ~210k miles. When I did a little research it seems that they don't get rebuilt but replaced. They are quite pricey too.

Jim, I'm trying to remember when, but I think it was late '04, my wife ordered a Mini. About the only way you could buy one at that time was to order it. Try as I might, I couldn't talk her into a manual, so the only choice was the CVT.

As another poster mentioned, there is no way to check and change the fluid as we are accustomed to with a typical automatic transmission. I can't remember what it cost, but it was an outrageous charge to flush and change the fluid. Well over $200 as I recall. When I learned that the only alternative if the transmission spit up was a new one at the dealer for $8K, we did not hesitate to spend the outrageous amount of money for the oil change.

She loved the car, but she drives alot and I was getting gun shy when it hit the 200K mile point, so she traded it off.

It never gave a bit of trouble and she was fine with driving it. When she wasn't in the car I used the sport shift and it was no different than manually shifting a typical automatic transmission.

I will say this about the car in general. When she got it I put a heavy rear sway bar on and that thing was every bit as much fun to drive as a go kart. It is decieving to look at. You glance at it and you just think it's another small econobox, but look harder and you will notice that the wheels are at the far corners and the body is wider at the bottom making even a wider track. It's an absolute HOOT to drive one. Sorry to get away from your question with this paragraph.

Hope this is useful.

Zulfiqar · #15 10-18-2012, 09:40 AM

CVTs are the money making golden egg machine as if there is anything not working right, only a handful repairs are possible - out of that spectrum - Its a $5K plus slap on you.

Fluid change - even at DIY level is expensive, $20/qt and about 7 to 9 qt capacity in a small/medium unit.

The torque convertor type CVTs do make sense but the solid wheel Honda unit did not - why use a motorcycle type system for standstill when the TC has been doing that very nicely for decades.