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Old 02-16-2009, 12:50 AM   #1 (permalink)
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Question CVT coasting in Neutral?

My 2002 CVT Insight has only 31000 miles and a LMPG of 39.4. I suspect the combination of a heavy foot and low daily stop and go mileage in the city is to blame. Nonetheless, even when driving pretty compulsively I have never gotten good "Insight level" mileage. Recently I have tried shifting into neutral in anticipation of stopping and have increased city mileage by 10% or so. Engine drag appears to be substantial for me with just coasting in drive, and my battery indicator is almost always topped off it seems. Am I damaging my transmission? If so, how. I presume the engine is still running so lubrication should be occurring - or am I wrong? Most all the discussions in the forum center on Manual transmissions, and my searches have not found a definite answer, although opinions abound.

Thanks for your help.

David - Dallas
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Old 02-16-2009, 07:53 AM   #2 (permalink)
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I would think dropping your CVT into and out of neutral won't really harm anything, but it may be adding a small amount of wear and tear that is totally unnecessary. Lubing will still occur, everything will work as needed, you just will be in neutral. This may prove problematic if you need to make a sudden maneuver to get out of the way of an accident... so I would suggest extreme care when coasting.

Taking your foot off the accelerator will result in the battery charger gadgets in the wheels to engage slightly and recharge the main battery (I know I'm not using the correct terminology, but rest assured, if I am misquoting or misrepresenting anything, the good people here at IC will immediately chime in and gently correct me) resulting in three or four bars to appear on your battery charging gauge. Pressing the brake pedal will really engage the little rascals (and you don't even have to pres the brake pedal. Just the act of turning on the brake lights with a normally-open pushbutton switch will accomplish the same thing) and result in substantial retardation, along with many more bars on the gauge (sometimes, at maximum retardation, the whole left-side arc will light up). That's the "engine drag" you feel, and is an artifact of our hybrid drivetrain.

My SOC gauge fluctuated down to half-charged in normal driving until Honda did the battery module update, and since then, I have not only not had a recal of any sort, but the battery SOC has never dropped more than two bars from the top, even in spirited driving. So having your gauge almost topped up as a matter of course is normal.

Put 50 pounds in the tires, anticipate stop lights, drive as though you have a fish bowl on the dash, maintain speed when possible, avoid stops without auto-stop (in these frigid days here, you can force autostop by shutting your climate control to "off" just before you come to a prolonged stop, you can restart it right after the engine shuts off and it won't restart the ICE), and avoid those dreaded jack-rabbit starts as much as possible. Your mileage will vary, but it will improve.

As opinions abound, the above is strictly my own observations and sugestions. Since you just got the car, and you feel diminished by the shameful LMPG, I would also suggest that you reset the LMPG to reflect your loving care of your new (to you) Insight, even though opinions abound here too, with some urging a carved-in-stone LMPG never to be altered, regardless of prior owner ignorance or abuse, like a scarlet letter to be forever endured by your hapless car. I, on the other hand, am more forgiving, and tolerant of fresh starts...
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Old 02-16-2009, 05:55 PM   #3 (permalink)
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I would think dropping your CVT into and out of neutral won't really harm anything, but it may be adding a small amount of wear and tear that is totally unnecessary. Lubing will still occur, everything will work as needed, you just will be in neutral.
Are you sure about the lubing? If this were the case, wouldn't there be an option to tow the Insight as a toad? I didn't think this is an option for the auto-tranny Insight, although the older CR-V with auto-tranny permits this with specific steps for putting the car in 4-down mode.

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Old 02-16-2009, 06:32 PM   #4 (permalink)
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Yes, there would still be lubing going on as long as the engine is on and you're not coasting down for miles from the top of Mt. Everest or something silly like that. But towing it behind something with the wheels on the ground and the transmission in neutral, why, that's just crazy talk (as Homer would say).
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Old 02-16-2009, 08:02 PM   #5 (permalink)
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It may be crazy talk, but it's pretty common for people who own a motorhome (as my folks do). There are fewer and fewer automatics out there that can be towed as a toad (see how that rhymes?).

Thanks for the response.
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Old 02-23-2009, 06:15 PM   #6 (permalink)
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I would expect that if towing or driving in neutral were issues that the owners manual would have warnings?

I seem to recall that the Prius has warnings about that, since MG2 is always engaged, it will generate lots of voltage if pushed, even with the car off, and the presence of voltage with the car off can damage the inverter.

Has anyone tried pushing a CVT in neutral, to see how easy it is?
I have not studied the CVT manual, but suspect that it has to have a clutch that disengages the tranny when stopped either in or out of gear?
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Last edited by Mike Dabrowski 2000; 02-23-2009 at 06:17 PM.
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Old 08-31-2010, 05:44 PM   #7 (permalink)
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I was also wondering about this. My battery stays usually 1 bar from full. I noticed when I try to coast in some downhill areas, I have to press the gas pedal to maintain a speed. Today I tried shifting in neutral and the car took off and I had to apply brakes to slow down. I also looked at the charge/assist light and nothing lit up when coasting or applying brakes.

I was wondering if this would damage the CVT. Also, when shifting from N to D should I apply the brake or just shift?

Sorry, but I am still learning.
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Old 08-31-2010, 10:59 PM   #8 (permalink)
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I am new at this as well. Here is what I did to determine the best mode. Change your speedometer display to Metric. On level ground you can find the sweet-spot where your economy goes to 1l/100km. This is about the rate you idle at when you neutral coast. You can learn to feel this point. Then you can switch back to Miles mode.

You will get the best mileage if you AVOID using IMA. (Don't boost/charge.)
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Old 09-01-2010, 01:58 AM   #9 (permalink)
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I was also wondering about this. My battery stays usually 1 bar from full. I noticed when I try to coast in some downhill areas, I have to press the gas pedal to maintain a speed. Today I tried shifting in neutral and the car took off and I had to apply brakes to slow down. I also looked at the charge/assist light and nothing lit up when coasting or applying brakes.

I was wondering if this would damage the CVT. Also, when shifting from N to D should I apply the brake or just shift?

Sorry, but I am still learning.
There has been some discussion about coasting and auto stop with the CV transmission that occurs at speeds below about 4 MPH in another thread. Built into the CVT is the start up clutch which allows low speed coasting and provides a "soft start" fluid-clutch-like capability for the variable speed band/pulley arrangement which is designed for zero slippage. Honda engineers set the 4 MPH limit in auto stop probably as a conservative speed at which to engage the start up clutch and to limit excessive wear Please consider the start up clutch to be puny and vulnerable to wear and not to be compared to the manual transmission clutch which can stand a lot of abuse.

With the CVT, coasting in Neutral and then shifting into Drive above 4 MPH subjects the start up clutch to overheating and wear for which it was not designed in my opinion. Conventional fluid coupling auto transmisions can withstand this sort of abuse more readilly mostly by overheating and should not be compared to the Honda CVT. The start up clutch is the Achilles heel of the Honda CVT. Abuse it and you will lose it. When it starts to go, metal will start to flake off and fill your CVT with abrasive particles that will soon demolish the rest of your transmission. If you subject your transmission to abuse, drain the fluid frquently and be sure to refill with the Honda CVT fluid but even that may not be enough.

To sum up: Coasting in Neutral may be okay if you do not shift back into Drive at speeds above 4 MPH. Coasting can be fun but do you want to risk destroying your CV transmission to gain a few extra MPG?

Hugh-Falls
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Old 09-01-2010, 09:53 AM   #10 (permalink)
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I totally agree with Hugh-Falls comments.....The CVT is not like other conventional automatics. IMO, it is a clever design but alot of the long term reliability depends on the wear of the start clutch. It was only intended to engage at speeds less than 10 MPH....(it starts to engage when you press down on the throttle and completely engages by 10-15 MPH)...Could you do the high speed coasting like once a year at 50 MPH and not see any problem?....Probably.....However, doing something like that on a normal basis (everyday event) would likely cause damage or very early wear on the start clutch and perhaps put a huge stress on the belt.

Either failure is very costly and vastly outweighs any fuel cost savings that you notice while coasting at high speeds.

I recommend that you do not do it.

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