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The gearbox from the car I'm rebuilding (Skoda Estelle '72, rear mounted engine, RWD, manual transmission) has the following problem:

  • I can shift up/down with engine off
  • I can shift up/down with engine on, car static, by keeping clutch pressed
  • I can shift up to any gear while running
  • I can shift down to from any gear while running EXCEPT engaging 1st

When I want to shift say from 2nd to 1st while running, I can't without "rasping" the 1st pinion a lot, like this gearbox has a "direct" 1st. I'm discarding clutch problems, since otherwise every gear would have such problems. I tend to think it is something with the 1st/2nd synchro. My question is: would it be its friction rings?

What else can yield that symptom?

UPDATE:

Reading its Haynes manual it says "Synchromesh: on all forward gears". So it implies 1st gets synchronized, right? In my case, it is almost impossible to get back to 1st without almost stopping the car.

enter image description here

UPDATE (July 10th, 2017):

Yes...it has synchromesh. I wonder which component of it, on this design, could make the issue (impossible to shift 2nd to 1st while moving)

enter image description here

  • On every manual I've ever driven, its pretty hard to shift to first in motion. Do you mean moving or engine running but car stationary? I know we have a question about this somewhere, I'll try to find it. – Zshoulders Jan 27 '17 at 5:05
  • The purpose of first gear is to move of from stationary. Why would you want to shift to first whilst the vehicle is still in motion? – Steve Matthews Jan 27 '17 at 9:19
  • @SteveMatthews It's really annoying to be forced to come to a standstill to be able to engage in 1st gear. And while driving traffic jams speeds(5-10km/h), it's not quick to try and drive off in 2nd gear, or you have to abuse your clutch. That is, in many older cars, with the older 4 gear transmissions. – Bart Jan 27 '17 at 9:48
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    Might I suggest you learn to double declutch, more info here; en.wikipedia.org/wiki/Double_clutch_(technique) – Steve Matthews Jan 27 '17 at 9:49
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There's much older cars that don't have their 1st gear synchronised. My '76 Triumph TR7 doesn't have it, and I bet your Skoda doesn't have it either. You either have to come to a complete standstill before you can engage 1st gear, or you'd have to double declutch. The latter requires quite some exercise to master. Reverse gear isn't synchronised in much (older) cars either, not even in all today's cars.

Edit: Since @Chenmunka confirmed that it's very plausible that this is your problem, i felt it's useful to elaborate somewhat about double declutching. I was really annoyed by the fact that i couldn't engage in first gear while rolling, especially in traffic jams it's really frustrating.

Double declutching in 1st gear is a lot easier than at higher speeds. (and i assume here that no one engages 1st gear while driving highway speeds)

You have to declutch, put the transmission into neutral, then you let go off the clutch again. Now comes a bit of feeling and experience into play.

Rev up the engine a little higher than you'd expect the engine to run when you would have been engaged in 1st gear. When in 2nd gear, you usualy have to rev about 1.5 times as high. If you've done well, the clutch now spins a little faster than the engine. As soon as you declutch, the clutch's speed will decrease, causing it to eventually run exactly as fast as the engine.(after half a second or so) Then you can engage in 1st gear. The more you exercise, the faster it'll go.

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    I can confirm this. I used to have a '71 Skoda S100 which is the same engine/gearbox as the Estelle. There is no synchromesh on 1st or Reverse. – Chenmunka Jan 27 '17 at 9:08
  • So what you're telling the OP is: Not being able to easily shift into first from second is normal, right? Also, there is a 1st to 2nd synchro, but it doesn't work both ways. If you look at the diagram, I think it's #28. – Pᴀᴜʟsᴛᴇʀ2 Jan 27 '17 at 11:11
  • @Pᴀᴜʟsᴛᴇʀ2 Yeah that's about it. 'not easily' being defined as 'you have to double declutch or come to a complete standstill'. Second gear is synchronised, so shifting to 2nd from any gear, even reverse, will be smooth. This counts also for 3rd and 4th gear. Shifting to 1st from any gear won't be smooth. Much really old cars with a 3 gear box(30s era) only had their second gear synchronised, because you come along that gear the most. – Bart Jan 27 '17 at 11:25
  • Good answer, but I would also say that with more recent cars, it is more probable that the first gear synchro is worn than being unsynchronized. None of the manual transmission cars I have driven allow easy engagement of 1st at speed, even though all had the 1st gear synchronized. Strangely enough, one (a 2011 Toyota Yaris) did crunching sounds when attempting double-declutching. – juhist Jan 27 '17 at 20:17
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    @AramAlvarez ...When trying to engage 1st, since the gear is spinning much faster than the output shaft (because of the typically high ratio of 1st gear), it takes much longer for the 1st gear synchro to match the speed of the input shaft with the speed of the 1st gear. For this reason, it is generally very difficult to shift into first while moving, unless you double-clutch (described in Bart's answer quite well). When you double-clutch, you are "manually" matching the speeds of the input and output shaft, at least close enough for the synchronizer ring to make up the rest of the difference. – Shamtam Jan 30 '17 at 4:02

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