driving manual questions

[powertrip]

Originally Posted by cantaloupe

Yeah, I think I heard the grinding noise as I was going from 2nd to 1st since I was coming to a stop sign.

most manual transmissions in cars dont have synchros in 1st gear. so downshifting into 1st while moving in just about any car can cause it to grind. it can be avoided but its not at all uncommon for this to happen, just gotta be very gentle putting it in while coming to a stop.

[JonnyRocket]

Originally Posted by SuperDave

what if you don't hear the gear grind like that, but you feel the gears grinding or crunching when shifting, with the clutch pressed down all the way? sometimes i feel like it's not as smooth as other times, though i've never heard my car do that before.

secondly, sometimes i'm unable to shift into 2nd from 1st, and i can only go straight into 3, i think 2nd gear is probably the only gear i have weird issues with, sometimes i can't shift into it properly...

If you don't hear the grinding noise from the video, you're not grinding the gears.

But this rough 2nd gear shift is proving to be common to our car unfortunately. When you feel the gears engage (typically on a cold 2nd gear shift), what you're feeling isn't necessarily bad for the tranny. That is not grinding that you're feeling. Just take it easy with that shift when cold, plan on a little extra time.

I've had it refuse to go into the 2nd gate as well and I've found that simply releasing pressure on the stick and trying again has worked. If you're familiar with double clutching, some have said that helps as well.

[cantaloupe]

Originally Posted by mankarn86

1. Grinding gears accidentally for a moment won't harm anything.
2. This is normally called "lugging" the motor...in theroy you are putting more load on the enigne...but for moment here or there it's okay.
3. It's not easy to accidentally knock a gear into neutral...esp out of 6..if you did it's not a big deal, just shift back into gear.

Lugging the motor - I know I've had it to the point where the engine was so strained, the car shook like crazy and it sounded like it was going to explode. I assume that wasn't too good for the car.

What about in less extreme situations? Is that still considered lugging the motor? Where you still feel a slight rumble? Like downshifting to second at a stop sign but just rolling slowly through the stop will cause that rumble as you press on the gas.

[SuperDave]

Originally Posted by JonnyRocket

If you don't hear the grinding noise from the video, you're not grinding the gears.

But this rough 2nd gear shift is proving to be common to our car unfortunately. When you feel the gears engage (typically on a cold 2nd gear shift), what you're feeling isn't necessarily bad for the tranny. That is not grinding that you're feeling. Just take it easy with that shift when cold, plan on a little extra time.

I've had it refuse to go into the 2nd gate as well and I've found that simply releasing pressure on the stick and trying again has worked. If you're familiar with double clutching, some have said that helps as well.

yeah i've double clutched and it's worked but that's annoying, i've tried rev matching and that doesn't help either. this is a weird quirk to the transmission.

[einzlr]

Originally Posted by cantaloupe

Yeah, I think I heard the grinding noise as I was going from 2nd to 1st since I was coming to a stop sign.

When you're approaching a stop sign, take it out of gear, let the clutch out, come to a complete stop, engage first, then go. Avoid trying to go into 1st while you're still moving; most MTs hate that.

[cantaloupe]

Originally Posted by einzlr

When you're approaching a stop sign, take it out of gear, let the clutch out, come to a complete stop, engage first, then go. Avoid trying to go into 1st while you're still moving; most MTs hate that.

I don't go into 1st while coming to a stop. I know it's a bad habit, but I just slow down enough and downshift to second then continue on. I'm just wondering if that is considered lugging the motor when I feel that slight vibration since I was going pretty slow.

[Jayde]

Originally Posted by cantaloupe

I don't go into 1st while coming to a stop. I know it's a bad habit, but I just slow down enough and downshift to second then continue on. I'm just wondering if that is considered lugging the motor when I feel that slight vibration since I was going pretty slow.

If I not I'm coming to a stop, I usually down shift to third and engine brake/brake down till the rpms hit 1,000 or so then shift into neutral and brake the rest of the way.

[einzlr]

Originally Posted by cantaloupe

I don't go into 1st while coming to a stop. I know it's a bad habit, but I just slow down enough and downshift to second then continue on. I'm just wondering if that is considered lugging the motor when I feel that slight vibration since I was going pretty slow.

Well at a stop sign, that'll damage your wallet and your license by getting you a ticket. But there are plenty of other situations where you slow without stopping before you accelerate again, and for those it's really a matter of heeding the revs. If you're at a crawl, you're going to want 2nd, but you might need to get the revs up to get into gear. If you're feeling the vibration while you're engaging the clutch, then that's what's happening. The signs that you're in too low of a gear are that the car bucks (lurches) and the engine feels like it's going to stall. It's a little hard to describe this sort of thing with words. If you know someone who's experienced with MT, ask if they'll go out with you some time and help you get a feel for it.

[ron wright]

Maybe just a technicality, but in modern transmissions with syncromesh, the transmission gears are always meshed together, so you can’t really grind a gear if you engage the clutch too soon during a shift. What you are actually grinding are the syncromesh sleeve ring teeth against the gear syncro teeth. Syncromesh is kind of hard to visualize if you haven’t been into a transmission before, but here is a nice video that does a pretty good job of describing and illustrating how the syncromesh works.

To get the syncros to grind required precise timing. You must wait just long enough for the gears to have matched speed so that you can push the syncro sleeve past the syncro blocking cone, then release the clutch before the syncro sleeve engages with the gear syncro teeth. Because there are so many syncro teeth being bumped together during this ‘grinding’ the individual pressure on each tooth is not much, so even though it sounds horrible, the actual wear on the syncro teeth is not much.

[einzlr]

^^^^ Also, howstuffworks.com used to have a good article explaining syncros; maybe it's still there.

[ST185RC]

Originally Posted by cantaloupe

How do you fix the gears if they aren't meshing correctly? So, if you only shift partway on accident due to notchiness, does this cause the gears to grind? Because it does sound like a clicking/grinding noise when it happens. It's not very loud though.

If it's difficult to get into gear, hold on to the clutch, put it into neutral and release the clutch, then clutch in again and try going into gear again. You can blip the throttle while you are in neutral if you don't want the engine to work as hard to get it back up to speed, but this is in essense double clutching. On old cars sometimes it's sticky going into reverse or first gear, double clutching helps you get into gears.

Syncros have come a long way since they were first introduced but still aren't 100% especially with temperature fluctuations. In my opinion double clutching is still a very useful skill to have. It's not just some ricer term from Fast and Furious.

[serialk11r]

For the lugging thing, I'm pretty sure that as long as there's no noise and vibration the engine isn't really being harmed as the engine doesn't produce much torque at low rpm anyways, but with these smaller 4 cylinder engines you usually want to be in 2nd at the highest when taking off, and 3rd will sorta work but it's a little embarassing waiting for the revs to climb off idle. To accelerate you want to be above 1500rpm at the very minimum, and 2000 before giving it nearly full or full throttle. It might be a bit hard to tell how the engine is doing in most cars since your typical car is pretty well insulated from engine noise, but shaking and knocking sounds are indications of poor combustion stability.

It's totally okay to roll around at very low loads and barely over 1000rpm (all automatic transmissions hold gear down to a bit over 1000rpm), but to accelerate perform a downshift first. Bigger per cylinder displacement usually means the engine runs better at lower speed, which is why 6 liter American V8s are sometimes geared for under 1500rpm at highway speed, as they can run at slightly higher loads at those speeds.