- CVT's are proven to be a bad idea, yet most are CVT (and reports of shudder are EVERYWHERE).
what is 'shudder', and why does it happen?
Depends on the model and the type of CVT.
There is one successful type out there, it was a chain and sprocket type gearbox with a mountain-bicycle type setup. Catch is, this uses a chain, and chains can only be so strong and still be a reasonable size. It was 'clunky' when chaning gears, but still had many more than a traditional auto could ever fit.
I believe it was in a small Kei Car in Japan; small Mitsubishi ute maybe? I'd have to go google again.
Most these days use a belt and cone type setup. allowing a belt to slide up and down ridges on two opposite facing cones.
The two main causes of CVT shudder share a similar component, and the third is electrical.
First, the belt can stretch. pretty common once the car gets older. This causes it to slip or hesitate on one 'cone' and not the other. This slip-grip type behavior is one cause.
Second, is when the fluid is wrong, worn, or just 'poor' from design. This sounds unlikely but with our climate is SUPER common. Honda Jazz' for example offered free CVT gearbox replacements if under 150'000kms and experiencing shudder. This was because they decided there was no need for a special CVT fluid for Australian climates.
I love Honda, but sorry guys, you were dead wrong.
3rd is electrical. And it's not always the gearboxes fault, but is made evident by the type of gearbox it is.
If the gearbox stops reporting load, or a sensor starts saying "5% throttle, she'll be right" when really its 95%, then unlike a regular Automatic, it wont allow the bands to move.
You can imagine how two cones with a belt between them, so basically unlimited combinations of 'front cog' to 'rear sprocket' ratios; with absolutely no idea of real engine load, might become an absolute pig to drive.
Honda went back to traditional Autos.
Mitsubishi the same.
Toyota didnt even try bringing their CVT models to Australia.
I'm sure I could keep listing if I bothered to research a bit more; but its just one of thsoe things where you hear enough horror stories, and there is a better replacement anyway, you justy dont 'risk' the inferior tech.
- @~thehung likes this