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What's the damage from grinding gears? (long)

Old 05-30-2006, 11:04 PM
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What's the damage from grinding gears? (long)

I've had my car over 3 months and have never grinded (ground?) gears. I even pause in neutral—almost imperceptibly—when changing gears just to make sure I get a smooth, perfect shift every time. Which I do. The 8 is the one thing in my life I try to keep perfect. (I'm not like this with other things in my life—just the car.) If anything—no matter how small—happens to my 8, I do whatever needs to be done to restore it back to like-new, showroom perfection. Parts Departments love me.

Anyway yesterday I offered to let my friend drive my 8 and, sure enough, he ground the gears—going from 3rd to 4th—twice. Now, I already know that:
…this is not serious.
…transmissions are designed to absorb some minor abuse, so that people can actually learn to drive a stick.
…the gears were probably not damaged at all, it's the synchronizers.
…I shouldn't let friends drive my car if I'm this ****.
…I need therapy.

What I don't know is exactly what damage was done? Was there definitely some small damage? Scratches on the synchronizers? Rounding off the tooth of a gear?? What, exactly? And how much would it cost to put it back the way it was before my friend did this? I just want a transmission with gears that have NEVER been ground.

Thanks!
Old 05-30-2006, 11:19 PM
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Drain and refill your gearbox oil. Go with something like Redline MT-90
Old 05-30-2006, 11:45 PM
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He might have done a little damage to the synchros but I doubt it's anything more than that. It's also probably a blessing that it was 4th rather than 1st or 2nd. I wouldn't worry much about it as long as you're shifting into 4th without issues or grinding.
Old 05-31-2006, 01:00 AM
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Agree with ike on the issue...3-4 shift really isn't that big of a deal when it comes to the syncros...because the shift is almost ALWAYS smoother then the 1-2 shift. Another upside is that it'd be te syncros/dogteeth that were grinding, NOT the actual gears.

1-2 times is NOTHING for a transmission. I knew a friend that used to miss gears ALL the time...not sure why but he did. His USED car with 21K when he got it didn't even start havin problems till 60K.

I really think yur gonna have NO problems from that...that's nothing.
Old 05-31-2006, 09:30 AM
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Alright, thanks for the reassurance. I won't obsess about this any more.
Old 05-31-2006, 09:35 AM
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If im in a hurry and redline first I almost always grind 2nd gear.. it sucks. even if I go slow it will grind.. 1-2 synco is a POS.
Old 06-01-2006, 06:23 PM
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First to second shifts can be tricky when redlining the car ; a quick problem solver which will forever change and drastically improve your shifting with the RX-8 is the Short shifter from axialflow. Check it out!!!

www.axialflow.com
Old 06-01-2006, 06:43 PM
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I used to botch the 1 to 2 shift, until i realized that kicking the **** outta the clutch would help keep it from happening. i now, forceful depress the pedal and I never have that problem.

My suggestion: Try giving the clutch a litle more leg and see if that helps.
Old 06-01-2006, 07:32 PM
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Originally Posted by Skythe
I used to botch the 1 to 2 shift, until i realized that kicking the **** outta the clutch would help keep it from happening. i now, forceful depress the pedal and I never have that problem.

My suggestion: Try giving the clutch a litle more leg and see if that helps.
Full disengagement does make sense...of course, I always thought that was a gimmee
Old 06-01-2006, 08:21 PM
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Since the take-up point is slow low, you might as well boot the clutch all the way in. I can't see how you couldn't and not get grinding most days...
Old 06-01-2006, 08:34 PM
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^ 'cause most of the time, slipping it *just* enough to break the engine from the gearbox is all you need to slip the next gear in. Buttah-smooth too! About a second, gear-to-gear? *shrug* It's pretty #$!@ quick shifting, the revs drop like a stone.

1st-2nd is rather brutal in this car, so it does get the foot all the way in for that one. And a heartbeat longer pause between those two gears. I'm starting to get the hang of 'er..

Fine corellian freighter you got there, btw.

Last edited by missinmahseven; 06-01-2006 at 08:36 PM.
Old 06-01-2006, 09:17 PM
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I just got the car yesterday, so I haven't exactly had much time with it. I can only consistently get the 1st-2nd shift smooth as my old Subaru took forever to drop revs and so required slow shifts. I'm still getting used to how fast I need to shift for 2-3-4-5-6.
Old 06-02-2006, 12:11 AM
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Originally Posted by LionZoo
I just got the car yesterday, so I haven't exactly had much time with it. I can only consistently get the 1st-2nd shift smooth as my old Subaru took forever to drop revs and so required slow shifts. I'm still getting used to how fast I need to shift for 2-3-4-5-6.
That too was one of the first things I noticed when I first got my 8 a few weeks back. I was used to lolly-gaggin around in the shifts while waitin for the RPM's to drop on my Cobra...otherwise you'd wear yur syncros awefully quick.

I never used to really be comfortable with shooting through neutral when shifting from gear to gear, but it gets to be second nature with the 8. Now that i've learned it's the standard, i've grown to love it!
Old 06-02-2006, 01:12 PM
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Originally Posted by missinmahseven
^ 'cause most of the time, slipping it *just* enough to break the engine from the gearbox is all you need to slip the next gear in. Buttah-smooth too! About a second, gear-to-gear? *shrug* It's pretty #$!@ quick shifting, the revs drop like a stone.

1st-2nd is rather brutal in this car, so it does get the foot all the way in for that one. And a heartbeat longer pause between those two gears. I'm starting to get the hang of 'er..

Fine corellian freighter you got there, btw.
Thanks. I did all the modifications myself. She's the fastest ship in the fleet.

I've found the 'box to be finicky, and tricky to drive smoothly around in low to mid speed traffic. The take up point is quite easy to figure out, and it has to be one of the easier cars to drive in hilly stop-and-go. It is smooth if you get it just right, but you have to get it JUST right. Fast or slow, it doesn't seem to matter.

Double clutch downshifts, however, have become a thing of beauty in this car.
Old 06-02-2006, 05:51 PM
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Originally Posted by YT1300
Double clutch downshifts, however, have become a thing of beauty in this car.


um, double clutchin hasn't been around for many decades...

too much fast & the furious again?
Old 06-02-2006, 08:32 PM
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^^^ I double clutch most of the time unless in a situation where the extra quarter-second loss of acceleration time will kill me. 'Always do it on downshifts.

Have torn down one of my transmissions, from a Ford Ranger which I drove almost 200,000 miles. Tranny parts including synchros still looked brand new.
Old 06-02-2006, 11:29 PM
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I'm curious then...how do you double clutch in a car that's designed to be single clutched? I couldn't argue with the syncros lookin new, considering how they inverntion of them is what made single clutching possable...sooo...?

I'm just confused, as the RX-8 isn't designed to double clutch...so how could you?
Old 06-03-2006, 02:18 AM
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Originally Posted by New Yorker
Alright, thanks for the reassurance. I won't obsess about this any more.
Btw where in NY are you from man?
I live in Queens...
Old 06-03-2006, 03:51 AM
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Originally Posted by Stavesacre21
I'm curious then...how do you double clutch in a car that's designed to be single clutched? I'm just confused, as the RX-8 isn't designed to double clutch...so how could you?
Well, you just do it. It's like... an extension of rev-matching. It's for the smooth cruise. When merging onto a freeway, or passing, or otherwise needing absolute max acceleration, and don't wanna take the extra quarter second, then don't do it -- that's why the synchros are there. But try it sometime. Even if you wind it up to 25 MPH or so in first gear, your shift to second will be buttery-smooth, like another poster said, a true thing of beauty.

No car is "designed" to be single clutched or double clutched, you just do it, or not.

PS: I originally learned rev matching when I drove big rigs for a couple years. Good truck drivers who really understand rev-matching don't even use the clutch for shifting gears, only use it for starting and stopping.

Last edited by Freddie; 06-03-2006 at 09:10 AM.
Old 06-03-2006, 07:10 AM
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I stand corrected. Thanx for the info though...very interesting indeed
Old 06-03-2006, 09:36 AM
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^^^ Even more interesting, and very educational, is this thread:

https://www.rx8club.com/rx-8-discussion-3/why-you-dont-need-double-clutch-86365/

Great discussion of rev matching, double clutching, and transmission design, from some folks far more knowledgeable than I.
Old 06-04-2006, 05:05 PM
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Originally Posted by SSJ 909
Btw where in NY are you from man?
I live in Queens...
I'm on the Upper West Side. I pretty much only use the car weekends, so I park in an indoor garage in Harlem two subway stops away. Where in Queens? I lived in Astoria a couple of years.
Old 06-05-2006, 03:32 AM
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It is nice to see that I am not the only one that has the problem shifting from 1st to 2nd. Besides reverse, which I always let the clutch out easy anyways, the 1st to 2nd shift grind is inconvienient and embarassing at times. I have driven a MT for 20 years and have never had this problem. I have heard that a short shift kit is the answer, but I would still like to know what the problem is.!
Old 06-05-2006, 08:33 AM
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Once you get the hang of double clutching, not only your 1 > 2 upshift but yes also your 2 > 1 downshift will be smooth as glass. No, I'm not saying you should shift all the way down to 1st every time, like say, coming to a stop. But there are those moments when you are down to like 5 MPH in traffic, maybe coming up to a red light. Then presto, the light turns green. If you're good and you rev match with the clutch out in neutral, the transmission will just effortlessly slip into first and boom, you're outta there. Or, you can brutally force the transmission into first (listen to those synchros scream), which will actually take longer. Or, you can just stay in second and blast outta there from 5 MPH -- your engine will love you, and beware of whiplash.

1 > 2 upshift is even easier. Oh and having said all that, I do plan to get an upgraded shifter.

Old 06-05-2006, 12:00 PM
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The tricky part for me to learn with double-clutching has been the use of the brake in conjunction. I just don't think I'm that coordinted haha! I'm curious though.. do you rev-match when you upshift double-clutch, or do you just use neutral to give the engine time to wind down?

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