iNVAR Posted March 18, 2008 Share Posted March 18, 2008 Hi all. I've been digging through the search now for some time and have read that downshifting into 1 isn't easy on our cars. But even then, I'm not sure if this is normal. Double-clutching the downshift does appear to make things easier but there is still a pretty good amount of resistance in the shift, even at low speeds of <20MPH. I have tried pushing harder to get into gear and it does slip in, without grinding. Sometimes I don't bother with the double-clutching when I'm doing <15MPH in 2nd and it's still very difficult to put the shifter into 1. I punched in some numbers into a special spreadsheet I made and figured out that at 15MPH, I'm doing roughly 1600 RPM in 2nd, and that to maintain 15MPH in 1st, I would have to rev to about 2700RPM. Is a 1100RPM difference in engine speed really that huge of a difference as to be too much for the 2->1 synchros and therefore I pretty much have to double-clutch for that downshift unless I'm doing <10MPH? Also, I get a slight grind sometimes on the shift from 2->3, but again, my searches seem to indicate that a lot of people get that when shifting quickly. I don't believe I'm shifting very quickly (but I'm not sure. This is my first MT car), and the grind doesn't always happen and when it does, it's very slight. Still annoying. Is this something I should get looked at while the powertrain is still under warranty? Thanks in advance for any input. Link to comment Share on other sites More sharing options...
whitetiger Posted March 18, 2008 Share Posted March 18, 2008 i find that if i blip the throttle alittle, i helps, even if the revs are alittle higher than needed to match 1st gear speed. Link to comment Share on other sites More sharing options...
Emmo Posted March 18, 2008 Share Posted March 18, 2008 Like whitetiger said, rev matching is the key to downshifting to first in this car. Link to comment Share on other sites More sharing options...
syphax Posted March 18, 2008 Share Posted March 18, 2008 Not really sure why you'd be downshifting into first at all... usually by the time you've slowed down that much it's time to be braking to a stop and depressing the clutch. I have owned a number of MT cars (both hondas and subarus) and there normally is more resistance to shifting down to first at all but the lowest speeds (less than 15 is a safe bet). If you are grinding between 2 and 3 you are probably just missing the shift slightly. Semper ubi sub ubi. Link to comment Share on other sites More sharing options...
iNVAR Posted March 18, 2008 Author Share Posted March 18, 2008 wow you guys are quick. thanks very much for the replies. whitetiger, and emmo, i'm assuming you mean blip the throttle while the clutch is out and i'm in neutral during the doubleclutch? syphax, it rarely happens, but (being in nyc) once in a while, cars in the right lane will decide to slow down suddenly or completely stop, and rather than stop my car behind them and wait for a really huge opening, if i see that there is an opening immediately to my left to merge, but there is a car several car lengths behind me approaching, i prefer to get back into first so that i can merge and accelerate to speed quickly. i can't get the pickup for that in 2nd. as for the 2->3 shift, you're quite possibly right. i need to try and be a bit more observant tonight with my shifting to see how the car's reacting exactly. edit: also, so that resistance is normal? because when i push the shifter hard to push it in, there isn't a grind when i get it in gear... if it were the dog teeth causing resistance, wouldn't i get a grind? Link to comment Share on other sites More sharing options...
syphax Posted March 18, 2008 Share Posted March 18, 2008 Gotcha. We have to do a bit of aggressive driving at times out here, but probably not as much as in NYC! It's funny, because one of my co-workers just brought up the topic of double-clutching yesterday, and I was forced to admit it is not a technique I have ever used much. Anyway, in my experience, I would say that a bit more resistance downshifting to 1st is normal, and is in fact why the double-clutch/rev-matching technique is recommended. wow you guys are quick. thanks very much for the replies. whitetiger, and emmo, i'm assuming you mean blip the throttle while the clutch is out and i'm in neutral during the doubleclutch? syphax, it rarely happens, but (being in nyc) once in a while, cars in the right lane will decide to slow down suddenly or completely stop, and rather than stop my car behind them and wait for a really huge opening, if i see that there is an opening immediately to my left to merge, but there is a car several car lengths behind me approaching, i prefer to get back into first so that i can merge and accelerate to speed quickly. i can't get the pickup for that in 2nd. as for the 2->3 shift, you're quite possibly right. i need to try and be a bit more observant tonight with my shifting to see how the car's reacting exactly. edit: also, so that resistance is normal? because when i push the shifter hard to push it in, there isn't a grind when i get it in gear... if it were the dog teeth causing resistance, wouldn't i get a grind? Semper ubi sub ubi. Link to comment Share on other sites More sharing options...
Emmo Posted March 18, 2008 Share Posted March 18, 2008 You don't really need to be double-clutching, just blip the throttle with the clutch pedal depressed before you try to shift to 1st and you should feel the shifter go into first much easier. Link to comment Share on other sites More sharing options...
CarlJNgmail.com Posted March 18, 2008 Share Posted March 18, 2008 Yeah all this sounds normal for this transmission. The "grind" i think your hearing: Is it more of a crunchy feel between gears 2 and 3? Cause mine rarely goes into 3rd smooth unless I really feel the shift and wait for the gears to line up. Link to comment Share on other sites More sharing options...
MilesA Posted March 18, 2008 Share Posted March 18, 2008 Two parts to this answer: It is normal with almost any synchronized manual transmission to balk at going into 1st when you try to downshift at speed. The synchronizer resists going into gear until the speed of the gear matches that of the shaft it rotates on. The synchronizer has to work against the momentum of the other rotating parts, which takes time. The greater the difference in gear ratio, the more speed difference there is to overcome. I'm sure you've heard that whirring sound as some of the rotating parts of your transmission speed up on the downshift? The second thing is, it is really not necessary to downshift into 1st until the car is stopped, or nearly stopped. If your car is moving at all, you can usually just accelerate in 2nd gear. It is better to wait until you are stopped before putting the transmission in 1st. Not all that long ago, few cars had synchronizers on the 1st gear. Just like cars don't have synchronizers on reverse gear, the assumption was your car would be stopped, or almost stopped, before shifting into 1st. Link to comment Share on other sites More sharing options...
johnAWD Posted March 18, 2008 Share Posted March 18, 2008 I never shift into 1st until I am stopped. No need to. Link to comment Share on other sites More sharing options...
GTTuner Posted March 19, 2008 Share Posted March 19, 2008 Two parts to this answer: It is normal with almost any synchronized manual transmission to balk at going into 1st when you try to downshift at speed. The synchronizer resists going into gear until the speed of the gear matches that of the shaft it rotates on. The synchronizer has to work against the momentum of the other rotating parts, which takes time. The greater the difference in gear ratio, the more speed difference there is to overcome. I'm sure you've heard that whirring sound as some of the rotating parts of your transmission speed up on the downshift? The second thing is, it is really not necessary to downshift into 1st until the car is stopped, or nearly stopped. If your car is moving at all, you can usually just accelerate in 2nd gear. It is better to wait until you are stopped before putting the transmission in 1st. Not all that long ago, few cars had synchronizers on the 1st gear. Just like cars don't have synchronizers on reverse gear, the assumption was your car would be stopped, or almost stopped, before shifting into 1st. ^^^ Exactly. A syncro cone or ring is actually a brake. All it does is match the speed of the two gears you are trying to engage. Some trannys actually use friction material on the syncro cones to grab the gear surface better. Not sure if Subie does this but this type of syncro is very sensitive to fluid type/viscosity. I always double clutch on a 2-1 shift if I have to do that. That will save on wear and tear of the syncro cone. BTW, I have seen some late model transmissions with a sycronized reverse gear too. Link to comment Share on other sites More sharing options...
CodyItaliano Posted March 19, 2008 Share Posted March 19, 2008 i was reading. you also say you have trouble from 2nd to 3rd gear changes? is it mainly on an upshift? i also had this problem, which kept getting worse and was only overcome by shifting into 4th then back to 3rd. right now i'm getting a new clutch installed and i'll see if that was part of my problem. dunno how your clutch is doing but i'll let you know how this goes hopefully by the end of the week. Link to comment Share on other sites More sharing options...
GTTuner Posted March 19, 2008 Share Posted March 19, 2008 ^^^^ That is a worn syncro my friend. Link to comment Share on other sites More sharing options...
iNVAR Posted March 19, 2008 Author Share Posted March 19, 2008 thanks all for the replies so far. i guess my concern was that the 2->3 synchro might be messed up, along with the 2->1 one, but it sounds like what i'm describing is normal behavior, phew. Link to comment Share on other sites More sharing options...
what Posted March 19, 2008 Share Posted March 19, 2008 agreed with revving the engine up to get into first downshifting, it makes it easy, the faster your going the higher youhave to rev the engine to downshift into first easily. Like if your going 20 and downshift, you have to get your revs up to like 4k-5k. But then you will only be in first for like 1 second if your getting on it, then have to shift back to second. Mostly this is used in racing if your going around a sharp turn, works best if you know how to sidestep the brake and gas. I have never had any problem going from 2 to 3.. i havent had much grinding or anything. I have done plenty of shifting from 2 to 3 at 6500-7000 rpm. So I really have no idea what that could be. Sometimes when drag racing, I might miss the shift and get some grinding, but thats just cause I messed up. Link to comment Share on other sites More sharing options...
SBT Posted March 19, 2008 Share Posted March 19, 2008 You'll know you've down the 2 to 1 shift correctly if the car settles easily in that gear with no lurching or surging. If it lurches (slows down abruptly), then you've under-revved. If it surges (accelerates forward), then you've over-revved. You just need to get a sense of where to make the down-shift relative to the dropping RPM range on your tachometer (or by ear after you've gotten a sense of where it hits in the engine/transmission cacophony). That said, I'd only recommend doing this for an emergency maneuver (or for auto-crossing), not for daily driving as it is tougher on your drivetrain (particularly your clutch) if you don't get the downshift correct (see comment about lurching/surging above). WRT the snicking that you're getting between 2nd and 3rd, perhaps it's time to change out your tranny fluid. Don't know how long you've had it in there, but if you're over 30K and haven't changed it out, then I'd suggest doing that soon. Cold weather driving (and I presume you've had some of that), is tough on fluids and the double-cone synchros in our tranny's like fresh, clean fluid. Recommend getting some Subaru Extra-S fluid and changing out your existing fluids with that. While you're at it, do the rear diff too. Your diff will love you too. Do a search on Subaru Extra-S for more info. HTH, SBT - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
iNVAR Posted March 19, 2008 Author Share Posted March 19, 2008 Oops, forgot to mention that I recently (about 1K miles ago) completely replaced the tranny/front diff and rear diff fluid with Subaru Extra-S 75W90 already. It did appear to make the shifting a bit easier from 1 to 2 and 1 (when coming to a stop) when the temperatures were really low, but overall, it wasn't a huge improvement. Link to comment Share on other sites More sharing options...
SBT Posted March 19, 2008 Share Posted March 19, 2008 Oops, forgot to mention that I recently (about 1K miles ago) completely replaced the tranny/front diff and rear diff fluid with Subaru Extra-S 75W90 already. It did appear to make the shifting a bit easier from 1 to 2 and 1 (when coming to a stop) when the temperatures were really low, but overall, it wasn't a huge improvement. Then the snicking/grinding that you've mentioned could be a worn 3rd gear synchro letting your know that you're moving faster than it's capable of synching up the gearset. If it does it all the time, or gets more pronounced, then it will get to a point where you just live with it, and realize that it's not going to get better, or get it fixed. This would be covered under the 60K powertrain warranty. SBT - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
iNVAR Posted March 19, 2008 Author Share Posted March 19, 2008 Hmm, I'm at about 40K miles right now and about 15 months to go on the warranty... perhaps I will drive it for a little bit and see if I notice any change in the condition. What would happen if I got up to about 50MPH in 2nd, went to neutral, and waited for a few moments, and then clutched in and put it in third? Essentially double-clutching without rev-matching? If my 2nd->3rd gear synchro was going, this should definitely cause a grind/crunch, right, being that my layshaft should've slowed down. I'm sure doing this isn't very good for the tranny, but for diagnostics purposes this should reveal a worn synchro? Link to comment Share on other sites More sharing options...
GTTuner Posted March 19, 2008 Share Posted March 19, 2008 Then the snicking/grinding that you've mentioned could be a worn 3rd gear synchro letting your know that you're moving faster than it's capable of synching up the gearset. If it does it all the time, or gets more pronounced, then it will get to a point where you just live with it, and realize that it's not going to get better, or get it fixed. This would be covered under the 60K powertrain warranty. SBT Listen to him Subietonic, he seems to know his stuff:). Link to comment Share on other sites More sharing options...
Wales Garage Posted March 19, 2008 Share Posted March 19, 2008 it wasnt really designed to do it. Link to comment Share on other sites More sharing options...
GTTuner Posted March 19, 2008 Share Posted March 19, 2008 Hmm, I'm at about 40K miles right now and about 15 months to go on the warranty... perhaps I will drive it for a little bit and see if I notice any change in the condition. What would happen if I got up to about 50MPH in 2nd, went to neutral, and waited for a few moments, and then clutched in and put it in third? Essentially double-clutching without rev-matching? If my 2nd->3rd gear synchro was going, this should definitely cause a grind/crunch, right, being that my layshaft should've slowed down. I'm sure doing this isn't very good for the tranny, but for diagnostics purposes this should reveal a worn synchro? No, because you are letting the clutch out you are helping bring everything to proper speed. Quite the opposite. If you double clutch even an upshift, and gear clash is reduced, it is a worn syncro. Link to comment Share on other sites More sharing options...
iNVAR Posted March 20, 2008 Author Share Posted March 20, 2008 GTTuner, sorry, I'm confused. If I'm doing 50, and I'm in neutral with the clutch out and not applying any throttle, wouldn't the layshaft be spinning according to the engine's idle speed? And if I clutch in without first rev matching and try to put it into 3rd, wouldn't that cause the synchros to have to try to match the layshaft's speed to the output shaft speed? Link to comment Share on other sites More sharing options...
GTTuner Posted March 20, 2008 Share Posted March 20, 2008 Now I'm confused!!!! The input shaft would be spinning at engine speed, the rest of the trans would be road speed........I think, LOL. Link to comment Share on other sites More sharing options...
iNVAR Posted March 20, 2008 Author Share Posted March 20, 2008 Hehe, I'm just going according to what I thought I read on howstuffworks.com I could've misinterpreted it though, doh! Link to comment Share on other sites More sharing options...
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