Answer to CVT 'Start Clutch' Failures for the 4G City

One of the most significant change in the new 4G Honda City is the change of the gearbox from the 5AT back to the CVT gearbox that was first used in the 2G City. Unfortunately, seasoned Honda fans will remember well that this rather 'infamous' gearbox has a rather bad reputation for unreliability. Whether this reputation is rightfully or wrongfully given, it cannot be denied that a search on the internet will reveal numerous stories of 'start-up clutch' (its actually called the 'start clutch' but mechanics at Honda's authorized service and repair centers added the 'up' and many have called it 'start UP clutch' since) failures with early batches of the 2G City and even 1G Jazz. 

The 'Start (up) Clutch

Honda's 'start clutch' is actually a viscous coupling clutch pack that operates via hydraulic pressure compressing several clutch plates together to transfer drive from the engine to the front wheels. Honda actually has a patent on the use of a viscous coupling clutch on their CVT gearbox, which they called Multimatic, back when it was launched in the mid-1990s on the EK3 Civic.

With the early batches of 2G City and 1G Jazz, 'start clutch' failures usually started with noisy 'juddering' when moving the car off from stationary, being due to the slippage of the clutch plates due to wear and tear from friction during usage. Eventually the 'start clutch' will slip more and more finally and in  extreme cases, it will fail to move off from stationary because the clutch plates cannot engage, a condition much like having a worn clutch on a manual gearbox. Other symptoms included very bad fuel economy due to inefficient transfer of drive to the front wheels.

What I understood back then, was that the original 2G City had a different gearbox oil in their CVT-7 gearboxes than was originally recommended by Honda R&D in Japan. Instead of using CVT-F oil, it seems that early batches of City's had ATF-Z1 in their CVT gearboxes instead. While Honda originally certified ATF-Z1 to be suitable for use in their CVT gearboxes, eventually after rumours of 'start clutch' failures became rampant, they switched to the special CVT-F oil. 

I also once had a discussion with an LPL from Honda R&D in Tochigi about this and he too assured me that if CVT-F oil is used, the start clutch should not fail. He also strongly recommended a strict 20,000-25,000 oil change interval to fully ensure longevity of the CVT gearbox.

Other less common failures reported of the original CVT gearbox was of 'internal leaks', where leakage of the hydraulic fluids inside the gearbox caused a failure to hold the 'V pulleys' properly locked in position during drive. When this happens, the two V pulleys which holds the metal CVT belt starts to change ratio uncontrollably and the result is an unstable fluctuating rpm during drive. The CVT-7 gearbox in my own Jazz 1.5VTEC had this failure and I was lucky to get a new gearbox replaced under warranty.

The new CVT gearbox

Given its rather 'unfortunate' history, it is understandable that as the new 4G City comes with the CVT gearbox, Honda fans might start bringing up the start clutch problem again or potential buyers will be told by friends of this. I am not sure whether any other publication actually touched on this in this level of detail, but certainly when I learned of the CVT gearbox's return in the 4G City, I was very concerned.

Therefore during the press conference for the launch of the 4G City, I departed from my usual restrain (of holding back my questions) and decided to tackle this issue head-on. I asked a very direct question 'head on' to the City LPL about this issue. And I video'ed his response at the press conference for you to listen for yourself. The youtube video is below.

Notes from the City LPL response

Key point to note from the LPL's response is the confirmation that the CVT gearbox used on this new 4G City now employs the standard torque converter which replaces the 'start clutch'. The 'start clutch' was originally located at the end of the gearbox, where the final drive is located. But here, the torque converter is placed at the usual location, just after the flywheel and operates like a regular torque converter (photo on the left). There is no 'start clutch' in this CVT gearbox. So, the message from the LPL is crystal clear - as there is no 'start clutch' so 'start clutch' failures will never happen with this new CVT gearbox.

The other key point is that the CVT gearbox has redesigned internals and along with the use of newer low-friction CVT gear oil, internal oil leaks like what happened with my Jazz 1.5 VTEC is also not likely to happen anymore.

I guess in the end, the most significant thing is that upon my proding him, the LPL confirms that Honda is very confident that the unreliability issues that affected early batches of the CVT gearbox in the original 2G City (and 1G Jazz) have been resolved. 

So if you are considering the 4G City but have been having people telling you 'stories' about Honda's CVT 'start clutch' failures, rest assured that those are things of the past. They most definitely do not apply to the CVT gearbox in the new 4G City because it is of a different design/construction. 

The new 4G City really is a great package and is the best equipped car in its market segment at the moment and likely for some time to come. TOVA gives it a strongly recommended buy if you are in the market for a 4-door sedan from this segment.