When driving down a hill, I usually leave my gear to neutral and let the momentum carrying the car. I found if the speed reaches ~80mph, I won't be able re-enage the 5th gear without make a noise like it would when you do not step on clutch all the way. If I just step on clutch all the way and leavethe car slide, I can release the clutch and get back the gear without any noise.
It appears there is some kind sychronization issue at high speed that it can't go to the gear smoothly. I don't have gear problem except sometimes it takes a few try to go back gear.
Simply (and not very technically) put, the transmission has 2 "sets" of gears. One set spins at the same speed as the engine (via the clutch), the other set spins with the differential, which is connected to the wheels. When you're flying down the hill, the gears connected to the wheels are spinning away in there, fast enough to make a milkshake, while the gears connected to the clutch are (relatively speaking) standing still.
Trying to ram the gears together when they're spinning at such different speeds will cause "gear clash", as the spring-loaded synchronizers that help the gears to mesh smoothly just can't keep up.
If you insist on driving like this, you'll have to learn to partially "double-clutch". This is when the car is already moving, and the transmission is in neutral (or the synchros are worn out). You rev the engine to match the speed that it "should" be at in a particular gear, then (since both sets of gears are now turning at more-or-less the proper speed), you quickly push the clutch pedal down and shift into the correct gear before the engine-side gears have a chance to slow down. This usually must be done within 1/4 second or so, or you'll grind the gears.
-- Side-note: With a LOT of practice, it's possible to drive without using the clutch at all (except for starting off from a light). It happened to me years ago when my VW clutch cable broke. At the light, engine off, in 1st gear, light changes, turn the key, chugchugchugchug and I'm driving down the road in 1st gear. Get the revs up to where I would normally shift, let off the gas just a bit so I can pop the shifter into neutral, wait for the engine to slow to the "normal" speed for shifting, and gently slide the lever into 2nd. Rev, pop, wait, slide into 3rd. Same for 4th. To shift down, let the car slow, neutral, rev, gently into 3rd. A bit harder to shift down, but possible. Drove for about 3 miles that way (in city traffic) to the dealer where I bought a new cable, then to a garage for a big glob of grease, then another 5 miles home, where I changed the cable.
When I go downhill, I put my transmission in neutral. If I try to re-engage it, fifth gear will grind when I am going over 80 mph.
There seems to be some kind of synchronization issue. ___________________________________________________________
Options:
1.) When you want to re-engage, step on the gas until the engine revs are at the rpm corresponding to 80 mph in fifth gear. Then pull it into (only) fifth gear. You won't even need the clutch.
2.) Don't try to re-engage the gears - just let the fun continue.
3.) Option deleted as judgmental.
Not just dumb but ILLEGAL in every state. It falls under the section of DMV laws about having control of the vehicle.
The stress on the syncros is NOTHING compared to the stress on that clutch plate as it tries to deal with the centrifugal force on it. That plate is NOT designed to handle that without being clamped between the pressure plate and flywheel.
Wait until that plate explosively fails. It makes a LOT of noise and tosses part all over!!
no worse than shifting at 6500 RPM... Now clutches *do* explode but usually under ultra-high-RPM racing conditions...
That said, to the OP - if you are serious, knock it the heck off. if nothing else you aren't saving any fuel unless you're driving a real old car (most modern cars disable the fuel injectors completely if the car is in gear with the throttle closed and the engine is turning over a certain RPM threshold) and as others have posted, it's possibly unsafe and definitely illegal. just leave it in gear and control your speed with throttle and brake and/or downshifting if necessary
You honestly think that a 94 FACTORY Toyota Camry clutch is going to handle 6500 rpm? Also in shifting you don't just spin the clutch up from a standing start the way the OP is. AND you certainly don't miss the shift a few times as was stated.
I dunno, never having owned a Camry. I can tell you that the clutch in every car I've owned has survived it quite well, or at least as close to
6500 as I could get (e.g. a stock Stude V-8 won't spin much over 5200 with a brick on the gas pedal and the trans in neutral) remember, a redline a day keeps the carbon away :)
Seriously, I've run stock clutches in all my Vee-Dubs and I don't think that they are significantly different in design or construction than whatever Toyota uses... nor is 80 MPH in fifth anything close to redline.
Why not? The 'factory clutch' in my Corolla GTS (Hachiroku) handles 7000 just fine. Has for 260,000 miles.
Toyota is an understatement in over-engineering. My 200HP Supra has the same transmission my 145HP Celica GTS had. It's rated for 225HP, so it was really overengineered in the Celica.
On May 30, 1:51 am, "MasterBlaster" > when you do not step on clutch all the way. If I just step on clutch
uble-clutch".
t more-or-less
Thanks a lot for the helpful explanation and the tip on double-clutch. I don't have clutch problems yet, but I will try double-clutch next time. It seems not an easy task. I hate to grind the gears.
On coasting being unsafe, I'm not convinced. Coasting at 80mph definitely not safe but coasting at 70mph or lower seems fine. I won't do that in snow, road is wet, or the hill is too steep. There are other driving habits that are more dangerous than this.
While you're coasting down a hill at a "safe" 70mph, turn off your engine. This will simulate a stalled engine, or running out of gas, or some other mechanical problem. Notice how you now have no power steering, no power brakes (after a couple of pushes), and an extremely unsafe vehicle with no way to stop or avoid crashing into other cars at the bottom of the hill.
With the car in gear, the turning of the wheels (and therefore the diff, gears, clutch and flywheel) will force the engine to keep turning whether the engine is dead or alive. This keeps the power steering pump spinning so you can turn, "engine braking" helps control the speed of the car, and the vacuum created by engine braking keeps the brake booster "charged" so you can stop whenever you want.
Now you know why "coating in neutral" is illegal pretty much everywhere.
On Jun 5, 1:12 am, "MasterBlaster" > > definitely not safe but coasting at 70mph or lower seems fine. I won' t
Thanks for the explanation and advice. I will keep that in mind. One question, coasting is fine for short distance, correct? Manual transmission always goes to neutral anyway before stopping (eg. before reaching red light).
... no way to double- clutch to get it back INTO gear....
Well, you can stop without power brakes and you can steer without power steering. But if you're not used to it, it will certainly screw up your reaction times and lengthens your stopping distance. Many drivers just panic when they lose PS and PB.
Nope, still illegal to be in neutral in most places at an intersection because you have no immediate control. If someone is about to hit you, you may still have time to dump the clutch to get out of the way, but finding a gear also can be really difficult when an out of control semi truck is inches away from you...
That is from the cop that stopped me for coasting when I was young, he also said it was really easy to spot a coaster in neutral because they float down the hill. When the drivetrain is under load, the car squats and holds the road differently. I was lucky and only got a lecture instead of a ticket.
And the Semi part did happen to me years later. Had one come up over a blind crest on a one lane ice road with deep swamp on both sides. He was loaded with logs, damn it was hard to find reverse.... Then I realized the engine had stalled on me. I dumped the clutch and my Jeep started rolling back as he is making little jackknifes coming closer to the point I can't see his bumper under my hood before I got it going. Phew. Didn't kiss front ends... (The trucker did stop and say he would have come back to pull me out of the swamp at least...)
You really need control at all times.
Mike
2000 Cherokee Sport
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00 'New' frame and everything else in '09. Some Canadian Bush Trip and Build Photos:
That one is a lot less clear-cut than coasting (for which there are NO valid arguments).
Yes, holding the clutch in and being in gear at a traffic light lets you respond immediately to a situation where you have to move.
On the other hand counter-arguments include:
- Those laws were written in the days of non-synchronized first gears. Modern synchro'd first gears engage FAR quicker.
- If the clutch hydraulics, cable, or linkage should fail while sitting at a light, in gear, with the clutch depressed... you go lurching into cross-traffic or pedestrians unless you have a foot hard enough on the brake also (most people don't hold their brakes that hard).
- If your foot slips off the clutch, you go lurching into traffic or pedestrians
- Holding the clutch in greatly accelerates wear on the throwout bearing
- If the throwout bearing seizes and breaks the clutch fork on vehicles built that way... you go flying into cross-traffic or pedestrians.
- if you have a heart attack and die at the light, you go lurching into pedestrians and cross-traffic.
It may not be strictly "by the book," but what I do is stay in gear and hold the clutch at a red light UNTIL a couple of cars stop behind me, reducing the odds that I'll have to get out of the way quickly. Then I go to neutral and let the clutch out, and then put it back in gear when the cross-traffic light turns yellow (or the crosswalk signals start flashing) indicating that my light is going green within 15-30 seconds.
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