Skipping gears bad for the tranny?
12-07-2009, 03:43 AM
#31
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Originally Posted by buyos1717,Dec 6 2009, 07:14 PM
In my honest opinion, i don't think it should do any harm. Now, someone mentioned about how it won't change the shafts or something but i find that hard to believe. I'm not saying they are wrong but i don't see how you can not use the proper shaft but engage a gear...
I could be wrong but when you skip a gear i think you are only doing just that, skipping a gear. I'm not sure if there is much else going on in the transmission...
The one thing that compelled me to post is the link to the Honda service bulleting or whatever. The article is not saying what the OP is doing is damaging. The OP is putting the proper load on each gear when pulling up a hill in second then switching gears to sixth when coasting down the hill. If you aren't putting extra load when doing that, i think you are in the clear. The article released by Honda is talking about putting extra load by starting in first then switching to sixth on flat ground because you don't want to shift through all the gears. In this situation you would be putting an extra load on the tranny to try and power up to the proper sixth gear speed. It's kind of like Honda putting out an article about not trying to start your car from a standstill in sixth gear. You are putting a load on the sixth gear that it isn't meant to handle. Hell, i think if the OP tried to cycle through all the gears when going down a hill would do more damage because you are again putting a sixth gear load on 2nd gear.
Hopefully all this makes sense. My reading comprehension sucks and i'm exhausted from having to study for finals.
I could be wrong but when you skip a gear i think you are only doing just that, skipping a gear. I'm not sure if there is much else going on in the transmission...
The one thing that compelled me to post is the link to the Honda service bulleting or whatever. The article is not saying what the OP is doing is damaging. The OP is putting the proper load on each gear when pulling up a hill in second then switching gears to sixth when coasting down the hill. If you aren't putting extra load when doing that, i think you are in the clear. The article released by Honda is talking about putting extra load by starting in first then switching to sixth on flat ground because you don't want to shift through all the gears. In this situation you would be putting an extra load on the tranny to try and power up to the proper sixth gear speed. It's kind of like Honda putting out an article about not trying to start your car from a standstill in sixth gear. You are putting a load on the sixth gear that it isn't meant to handle. Hell, i think if the OP tried to cycle through all the gears when going down a hill would do more damage because you are again putting a sixth gear load on 2nd gear.
Hopefully all this makes sense. My reading comprehension sucks and i'm exhausted from having to study for finals.
Once the car is in GEAR its fine. Its getting it into gear that is the problem.
Honda is saying: If you're in first, to 9K rpm, then you clutch in, the input SHAFT is still spinning at 9K RPM (if its a 1:1 ratio). Now when you bang 6th gear, the synchro's job is to get that shaft spinning to the input shaft speed - which if you skip shift without pauses or anything, is 9K rpm.. from REST (pretty much) to 9K = big difference in speed.
Now thats an over-over simplification but thats the basic idea.
Your idea is that the "lugging" is whats bad for the trans - its not, its bad for the ENGINE only...once its in gear the transmissions job is done...
12-07-2009, 08:29 AM
#33
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I have a question... what about downshifting. Sometimes I'm in 5th and go to 4th gear with the clutch in but i dont engage but I engage when I am in 3rd(5th gear to 3rd gear but I don't engage in 4th). Is this okay?
12-07-2009, 08:34 AM
#34
The issue is NOT rev-matching. The issue is matching the input shaft speed to the output shaft speed according to the new ratio you have selected. This occurs when the clutch is pushed in, so engine revs really have nothing to do with it unless you are double-clutching and temporarily using the engine to change the speed of the input shaft before clutching back out and engaging the gear. Again, if you don't double-clutch, then rev-matching has NOTHING to do with synchro wear.
The short, short answer is that as long as you row the shifter through all the gears, the synchros won't be stressed any more than they would with normal shifts.
So if you want to go from 2nd to 6th, just hold the clutch in as you row through all the gears until you get to sixth, then clutch out normally. You'll probably find that the time it takes to row the gears is pretty close to the time it takes for the revs to drop, so it doesn't really cost you any "time" to do it this way and it spreads the load on the synchros across all the gears instead of dumping the entire job on sixth gear.
edit: slipstream beat me to the punch on this. But good to see there was at least one other person who understood how a transmission works.
The short, short answer is that as long as you row the shifter through all the gears, the synchros won't be stressed any more than they would with normal shifts.
So if you want to go from 2nd to 6th, just hold the clutch in as you row through all the gears until you get to sixth, then clutch out normally. You'll probably find that the time it takes to row the gears is pretty close to the time it takes for the revs to drop, so it doesn't really cost you any "time" to do it this way and it spreads the load on the synchros across all the gears instead of dumping the entire job on sixth gear.
edit: slipstream beat me to the punch on this. But good to see there was at least one other person who understood how a transmission works.
12-07-2009, 02:01 PM
#36
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basicially:
skip shifting is not recommended..
it will cause whats called lock out as previously stated..and
shifting from 2-4.. the 4th syncro will have to slow the speed of the input shaft down (twice)* as much as if you shifted from 3rd to 4th. thus causing faster syncro friction surface wear.. i dont know if i can say it any better and simpler.
if i do skip shift say 2-4.. with the clutch in (depressed) i shift from 2nd-3rd(with clutch still in) and then into 4th.. the 3rd gear syncro slowed down the shaft speed some more and then the 4th gear syncro sleeve easily slides over to the next gear. locking the syncro hub and gear together causing power to be transfered through that gear.
skip shifting is not recommended..
it will cause whats called lock out as previously stated..and
shifting from 2-4.. the 4th syncro will have to slow the speed of the input shaft down (twice)* as much as if you shifted from 3rd to 4th. thus causing faster syncro friction surface wear.. i dont know if i can say it any better and simpler.
if i do skip shift say 2-4.. with the clutch in (depressed) i shift from 2nd-3rd(with clutch still in) and then into 4th.. the 3rd gear syncro slowed down the shaft speed some more and then the 4th gear syncro sleeve easily slides over to the next gear. locking the syncro hub and gear together causing power to be transfered through that gear.
12-07-2009, 02:56 PM
#37
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this is what woodwork wrote a very damn long time ago...
https://www.s2ki.com/forums/index.php?showt...=0&#entry204419
I have seen many 6th gear sleeves that have been damaged.
The typical story is this: Stop light, 1st gear, engage the clutch, rev to 9,000 RPM, shift quickly to 2nd, rev to 9,000 RPM, same into 3rd, look down and find the car going 80 MPH on a city street and the engine noise is screaming, recognize that any cop is going to write a ticket. Shift to 6th quickly to lower engine noise.
Dragging the mainshaft speed down from 9,000 RPM to 4,000 when going from 3rd to 6th takes time. 6th gear has only a single synchro ring and it doesn't like it. It will grind if you are shifting hard and fast. By shifting hard the synchro ring does not have time to slow down the main-shaft and the sleeve will slip over the synchro and grind the gear. If the sleeve is ground enough in 6th then it will not slide the other way to engage 5th.
So if it is hard to get your car into 5th or 6th it may be because the sleeve is being damaged by skipping gears. Hope this makes sense
The typical story is this: Stop light, 1st gear, engage the clutch, rev to 9,000 RPM, shift quickly to 2nd, rev to 9,000 RPM, same into 3rd, look down and find the car going 80 MPH on a city street and the engine noise is screaming, recognize that any cop is going to write a ticket. Shift to 6th quickly to lower engine noise.
Dragging the mainshaft speed down from 9,000 RPM to 4,000 when going from 3rd to 6th takes time. 6th gear has only a single synchro ring and it doesn't like it. It will grind if you are shifting hard and fast. By shifting hard the synchro ring does not have time to slow down the main-shaft and the sleeve will slip over the synchro and grind the gear. If the sleeve is ground enough in 6th then it will not slide the other way to engage 5th.
So if it is hard to get your car into 5th or 6th it may be because the sleeve is being damaged by skipping gears. Hope this makes sense
12-07-2009, 06:20 PM
#39
^^^No it is the same idea.
I think that what confuses some people is that honestly you could drive with skipping gears for 100K miles and never have an issue with the tranny. That does not mean it is not bad on the tranny. All things the same a tranny that was driven 100K miles with skipping vs. one that was not will have noticeably more syncro wear, regardless of how it shifts. You may feel the negative effects of the wear after 10K miles (this is especially true with the K-series trannies), or you may not feel the effects until 100K, it just depends.
Most people now a days don't own a car for 100k miles, so alot of people may skip shift the entire life they own the car thinking that they are not harming the tranny. To bad for the person who owns the car next, and has to foot the bill.
I think that what confuses some people is that honestly you could drive with skipping gears for 100K miles and never have an issue with the tranny. That does not mean it is not bad on the tranny. All things the same a tranny that was driven 100K miles with skipping vs. one that was not will have noticeably more syncro wear, regardless of how it shifts. You may feel the negative effects of the wear after 10K miles (this is especially true with the K-series trannies), or you may not feel the effects until 100K, it just depends.
Most people now a days don't own a car for 100k miles, so alot of people may skip shift the entire life they own the car thinking that they are not harming the tranny. To bad for the person who owns the car next, and has to foot the bill.
12-08-2009, 09:30 PM
#40
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Originally Posted by slipstream444,Dec 7 2009, 08:38 AM
There have been several cars that have suffered the 5th and 6th gear "lockout" caused directly by skip-shifting. The damage is caused by excessive forces "mushrooming" the 5th and 6th gear synchros.