OK, I've owned my Cavalier since Day 1 and now have 117,500 miles on it. I drive 35 miles each way to work and back five days a week. In the last few weeks, I've encountered a situtation with my transmission where, as I leave the office in the afternoon I will grind first gear when attempting the initial shift. I know I have the clutch pedal depressed all the way down, and it seems that I have to pump the clutch and before attempting to shift into first again. When re-attempting to shift into first it will either go smoothly or there might be a slight grinding sound and then it engages. I know my slave cylinder is topped off and the car is still running the original clutch. I don't race the car, do hard shifts, or any of that other crazy crap. I'm wondering if my friction plate is getting worn. It has made a grinding sound into second once or twice, but nothing more than that.
Any ideas?
"Beer is proof that God wants us to be happy" - Benjamin Franklin
hey man, its your syncronizer for your first gear, sorry bro, my cavi is in the shop for the same thing, its costing me 1400 bucks thats alot, sorry bro.
Let me guess, you pre-shift into 1st when coasting to a stop?
2002 Cavalier 2200 5spd
Solid Snake wrote:Let me guess, you pre-shift into 1st when coasting to a stop?
Sometimes, but not often. Why would this mean anything?
"Beer is proof that God wants us to be happy" - Benjamin Franklin
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Sometimes, but not often. Why would this mean anything?
What the synchro does:
Every gear on your transmission has a synchronizer, or synchro. The synchro's job is to equalize the speed between the output shaft and the clutch. Say you shift from first gear to second at 2000 rpm. The 2nd gear synchro's job is to bring the flywheel from 2000 rpm to about 1400 rpm. The synchro absorbs about 600 rpm from the flywheel doing this, so the wear minimal. Now, if you take 1st gear to redline, the 2nd gear synchro will have to bring the input shaft down to 4000 rpm, dropping the shaft speed by 2000 rpm and taking more wear in the process.
What happens when the synchro dies:
When you start out from a stop, the wheels are stopped so when you depress the clutch and put the gear selector into 1st, the synchros job is to bring the clutch (input shaft) which is still spinning at idle speed to a stop, and a synchro in good condition does this fairly quickly. If your synchro is in bad shape, it will not bring the input shaft to a stop fast enough and you will get grinding. A failing synchro will not synchronize the input and output shafts on the transmission before the dog teeth touch the desired gear and this is what causes the grinding.
How you probably killed your 1st gear synchro:
Remember my explaination in the first paragraph about the synchro aborbing energy from the clutch to bring it up/down to speed? Well even in redline shifting, the synchro only has to absorb 2000 or so RPM. When you downshift early in to 1st gear when coming to a stop, say at 20mph, your 1st gear synchro has to raise the input shaft speed by 4000 rpm every time you do this. 4000 rpm is probably what your engine would be doing if you let out the clutch in 1st at this speed, so that is what the synchro needs to spin the clutch up to in order to prevent grinding. Downshifting into first gear early is probably what killed your synchro.
How to drive your crippled transmission without grinding:
Since your first gear synchro is probably incapable of slowing down the input shaft you can do one of two things to prevent grinding:
1. Make sure the input shaft is stopped so the dying synchro doesn't have to do any work. In other words, hold down the clutch for a few seconds to let the clutch spin down before putting the car into 1st gear.
2. Use your 2nd gear synchro to stop the input shaft before shifting into 1st. This is probably the best technique to use when you cannot anticipate taking off. If you get a sudden green light and need to go, put in the clutch, quickly shift (halfway) into second then put it in 1st, then let out the clutch. Your second gear synchro will now take over the work your first gear synchro used to do and you should not hear grinding.
I've said this many times in other posts:
DO NOT EVER DOWNSHIFT TO SLOW YOUR CAR. USE YOUR BRAKES TO BRING YOUR CAR TO A STOP WITH YOUR TRANSMISSION IN NEUTRAL OR JUST LEAVE IT IN THE GEAR IT WAS ALREADY IN. DOWNSHIFT ONLY TO GO AND EVEN THEN, DOUBLE CLUTCH WHEN POSSIBLE. BRAKES ARE CHEAP, REBUILT TRANSMISSIONS ARE EXPENSIVE!
If you have questions on double clutching or the way manual transmissions work in general, check out www.howstuffworks.com
2002 Cavalier 2200 5spd
So it is bad to put the car in 1st gear while rolling to a stop even if you leave the clutch pushed in? Wow, I am so glad I read this. I guess I have a bad habit to break...
Some argue that if you leave the clutch pushed in too long, your throwout bearing takes damage. The healthiest thing to do for your transmission when coming to a stop is to put it in neutral and let out the clutch. If you can anticipate your light turning green, push in the clutch a few seconds before putting the car into 1st and your 1st gear synchro will take no damage whatsoever. Your throwout bearing will be happy too since you're not on the clutch all the time.
2002 Cavalier 2200 5spd
Well, your explanation of how transmissions and syncros work is great; *however*, you made too many assumptions and are now getting people worked up over their shifting habits. I have never ever redlined my transmission in any gear. Also, in 20 years of driving many standards (cars and trucks), I've always downshifted to slow my vehicle to a stop. I don't just ram it into gear, but I downshift and lightly brake, and then downshift again. If you're going to preach that downshifting is BAD for the transmission, then I want you to go tell all of the Forumula One racers (that means real racing and not that NASCAR BS) that when they downshift and upshift through turns that they're tearing up their transmission.
You didn't even read my original post. I stated that first gear was grinding when I perform the initial shift. That means I am attempting to engage first gear. Luckily, I am a member of another automotive forum where I found someone who helped me diagnose a TPS/VSS problem where no one here had a clue. When I outlined the issue, he stated that GM redesigned the 1st/2nd gear syncro in 2004 because the 1st/2nd syncro in these cars tend to go out.
Thank you for your input, but please gather all of the facts first.
"Beer is proof that God wants us to be happy" - Benjamin Franklin
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I have never ever redlined my transmission in any gear.
This isn't the issue, I just used it as an example to illustrate that redlining into the next gear is only half as bad as putting your transmission in 1st at 20mph (yes, even with the clutch in).
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I've always downshifted to slow my vehicle to a stop. I don't just ram it into gear, but I downshift and lightly brake, and then downshift again.
Again this means nothing. Your synchros don't care about the brake or the clutch, they take damage simply by you putting the car in the gear. While downshifting, you're effectively doubling or tripling the wear on your synchros because you want to take the load off your $30 brake pads. Doesn't make too much sense, does it?
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You didn't even read my original post. I stated that first gear was grinding when I perform the initial shift. That means I am attempting to engage first gear.
I read your post completely and anybody who read my post as well would have known that. I know it's grinding when you attempt to engage first gear. I told you the exact behavior that caused your synchro to fail and I gave you two suggestions on how to use your worn transmission without grinding, did you try them?
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If you're going to preach that downshifting is BAD for the transmission, then I want you to go tell all of the Forumula One racers (that means real racing and not that NASCAR BS) that when they downshift and upshift through turns that they're tearing up their transmission.
When all those Formula One guys (and the NASCAR guys too) can show me an original transmission with 100,000 miles on it then I'll take your word on it. If you think F1 transmissions have much of anything in common with ours, your kidding yourself. These machines probably use computerized rev-matching so synchros are unnecessary (and likely cost 5x more than your whole car). There are transmissions out there with two clutches and some with no clutches at all, but we're not talking about those and unless you want to rebuild your transmission every day like the F1 guys do, I don't see the point you're making in bringing them up.
I told you why your first gear grinds and the driving behaviors that probably led to it. I told you how to change these behaviors so you can drive without grinding or causing unnecessary wear, but if you're unwilling to listen and want to keep using your $1500 transmission to save your $30 brakes, I'm not going to stop you. I've got a Getrag with 92K on it, still running the factory clutch, that will shift as fast as you can push it, but what do I know?
2002 Cavalier 2200 5spd
From the O'Reilly Auto Parts website:
Wagner Front Brake Rotor: $36.00 EACH
Wagner Semi Metallic Brake Pads: $43.99 per SET
Wagner Premium Shoes: $28.99 per SET
I won't do the math, but common sense tells me that is MORE than the "$30 Brake Job" you're trying to push on people. And that's doing the work myself and not an automotive shop. I don't go cheap on brakes, but even if I got the cheap parts and didn't change the rotors, I'd still be in for more than $30, and I didn't even add the bottle of fluid to the cost.
Snake,
The bottom line is that you're trying to put 20lbs of fertilizer into a 10lb bag and you're not succeeding. You've scared a few people who responded to this post, but you sure as hell aren't fooling me. I decided to poke around the Internet and ask more of my automotive friends about the possible reasons I am having problems. The funny thing is, nothing you stated was remotely close to the reason why my problem exists. The reasons I found were, 1) the gearing for 1-2 is too close, meaning the UPSHIFTS could be causing the premature failure, 2) there is a defect/design flaw in the 1-2 syncronizer (which I learned from a GM mechanic who told me GM upgraded the syncro in 2003), and 3) improper shifting wears on the syncronizers (banging gears, not depressing the clutch completely during a shift, speed shifting).
Sorry, but you're baffling people with BS. You're braking technique will also create more wear and tear on other components in the car, such as the tires and suspension. Bad braking affects gas mileage, plus leads to more downtime with more frequent brake maintenance.
"Beer is proof that God wants us to be happy" - Benjamin Franklin
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I won't do the math, but common sense tells me that is MORE than the "$30 Brake Job" you're trying to push on people. And that's doing the work myself and not an automotive shop. I don't go cheap on brakes, but even if I got the cheap parts and didn't change the rotors, I'd still be in for more than $30, and I didn't even add the bottle of fluid to the cost.
Yes, $30 for premium pads, doing the work myself. It's easy. Even at $100, it's a hell of a lot cheaper than the $1400 Greg is paying for the same thing.
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1) the gearing for 1-2 is too close, meaning the UPSHIFTS could be causing the premature failure
No, for several reasons:
1. The closer your gears are the less wear the synchros take on shifts. This is why skipping gears without double clutching causes more wear on synchros.
2. Your 1st gear synchro is shot. Nobody upshifts to first gear, only downshift.
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2) there is a defect/design flaw in the 1-2 syncronizer
There is no such thing as a 1-2 synchronizer. The same synchro that takes wear when you upshift to 2 takes wear when you downshift to 2.
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3) improper shifting wears on the syncronizers (banging gears, not depressing the clutch completely during a shift, speed shifting).
That much is true. Like I said before, downshifting to slow your car does this as well.
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Sorry, but you're baffling people with BS. You're braking technique will also create more wear and tear on other components in the car, such as the tires and suspension.
Sorry, it's not a technique, it's how you're supposed to bring your car to a stop. How do you think the automatic cars stop? Using the brakes to stop the car uses even braking force on all four wheels, while your downshifting uses two. Unless you drive the wheels into lockup, the tires don't take damage and neither does the suspension. Where do you get this from?
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Bad braking affects gas mileage
ALL BRAKING affects gas mileage because you are wasting the kinetic energy that would otherwise be taking your car further. I don't care whether you brake, downshift or release a parachute, you're reducing your mileage. I have a real-time MPG gauge on my car, so trust me, I know.
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plus leads to more downtime with more frequent brake maintenance.
Brake job = $30 + 2 hours. You're being penny-wise and pound foolish to an extreme. Brake pads are expendable, transmissions are NOT. You'll get a good taste of downtime and expense when your transmission gets dropped. I'm sorry this isn't what you wanted to hear, but hey, it's your car, not mine.
Like I said before, my 02 getrag has 92Kmi on it with the original clutch and the synchros work like a dream. It's all about driving style.
2002 Cavalier 2200 5spd
this is an extrememly rare case.
In a car's lifetime of about 150k miles .. the brake pads alone should be changed at least 4 times .... some may go longer some may need to be replaced sooner depending on driving habits ..
there is no guarantee that not downshifting will save your syncros .. I am willing to bet that the syncro would have gone out no matter what his driving habits were .. there was obviously something else in the equation that caused a failed syncro .. if downshifting causes a syncro to go bad do you realize how many people would have to have them replaced??
Yes, I understand your argument .. Its easier and cheaper to replace worn brake pads than to have a tranny repaired.
I don't believe your argument for one second that downshifting can cause premature syncro failure .. you have your opionion and I have mine and so does every mechanic and technician out there.
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I don't believe your argument for one second that downshifting can cause premature syncro failure .. you have your opionion and I have mine and so does every mechanic and technician out there.
If you know what a synchro does and when it's used, you'd know that there's no denying that downshifting to brake accelerates synchro wear. What you consider premature is completely subjective, to me failure at 100Kmi is premature. What I can garuantee is that not downshifting will extend their lifespans just like not burning out will extend the life of your tires. Unless you double clutch and RPM match, downshifting WILL cause wear on your syncros, this is a FACT. Downshifting causes MORE wear than upshifting because at least on the upshift you have the input shaft's natural friction to aid the synchro into bringing the clutch down to the proper speed. When you downshift without double clutching, this friction that aids upshifts works against your synchros on downshifts (not to mention the RPM difference is usuall more dramatic on braking downshifts). Every time you pop your transmission in 1st as you slow from 20mph, your synchro has to spin the clutch upto 4K RPM whether you let out the clutch or not. You can have your opinion, but I'm not giving you my opinion, I'm telling you what happens. You can believe whatever you want to believe, it's your tranny and like I said before, mine is as good as new. I've seen dead synchros before in my friend's cars and the common behavior they had was downshifting to slow the car. A friend of mine had a habit of putting her transmission into 2nd to slow the car and what do you know? Her 2nd gear grinds unless you take at least 2 seconds to shift.
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I am willing to bet that the syncro would have gone out no matter what his driving habits were
Well you'd lose money on that bet because I HAVE THE SAME EXACT TRANSMISSION (and engine) he has, down to the same exact year and mine is going strong at 92K with not even a hint of grinding. It's all about driving habits whether you want to believe it or not.
2002 Cavalier 2200 5spd
I completely agree 100% with EVERYTHING solid snake has said.
Take the mans advice and quit arguing something you have little concept over.
