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Old 03-07-2019, 12:01 PM   #11 (permalink)
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I shift to neutral for very long coasts, buf for anything 15 seconds or less, I don't bother.

Does going from neutral to a gear cause the syncros to work?

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Old 03-07-2019, 04:56 PM   #12 (permalink)
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Quote:
Originally Posted by redpoint5 View Post
I shift to neutral for very long coasts, buf for anything 15 seconds or less, I don't bother.

Does going from neutral to a gear cause the syncros to work?
If you were coasting at idle with the clutch engaged in neutral, then the transmission should be all synced up (like double clutching does), so in that case no.

15 seconds shouldn't bother the throwout bearing, I was picturing a 5 minute coast down and beyond a big hill holding the clutch the whole way.
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Old 03-12-2019, 04:58 PM   #13 (permalink)
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Quote:
Originally Posted by redpoint5 View Post
Does going from neutral to a gear cause the syncros to work?
Yes. The few times I have EOC'd the transmission was not happy about going back into gear for the bump start.

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Originally Posted by Shaneajanderson View Post
If you were coasting at idle with the clutch engaged in neutral, then the transmission should be all synced up (like double clutching does), so in that case no.

15 seconds shouldn't bother the throwout bearing, I was picturing a 5 minute coast down and beyond a big hill holding the clutch the whole way.
The bigger question here: Is the throwout bearing SPINNING when the engine is off, which I think it is not, in which case you can hold it down for as long as you want as long as the engine is off. I would definitely be shifting to neutral for a 5 minute coast though.
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Old 03-12-2019, 06:07 PM   #14 (permalink)
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I just swapped out the flywheel, clutch and throwout bearing on my M5OD-R1HD in my Explorer, so the mechanical relationships are pretty fresh in mind.

Note: assumes all parts working correctly.

When the clutch is engaged (foot off the clutch pedal), the clutch disc is clamped by the pressure plate and turns at the same speed as the flywheel. This, in turn, means the input shaft to the transmission is turned at the same speed as the flywheel. Niether the pilot bearing nor the throwout bearing is spinning at this time. If the transmission is in neutral, you can turn off the engine and coast with no wear on the pilot or throwout bearings. They'll be stationary.

When the clutch is disengaged (foot on the clutch pedal), the throwout bearing is compressing the springs on the pressure plate, un-clamping it from the clutch disc. The throwout bearing will be rotating at flywheel speed. Any difference in speed between the flywheel and the input shaft of the transmission shows up as rotational speed in the pilot bearing. If you turn off the engine, the throwout bearing stops spinning - no wear. The pilot bearing will still be spinning, though.

In either case, if you put the transmission in neutral, the input and output shafts will soon be rotating at different speeds. Re-sycing them to get into gear will require the syncros to do work matching the speeds, unless you start the engine first and do rev-matching. If you want to bump start, you either need to leave the transmission in gear or use the sycnros.

So, for EOC, you can choose: syncro wear (trans in neutral, clutch engaged) or leg pain and throwout/pilot bearing wear (trans in gear, clutch dis-engaged). You can do leg pain AND syncro wear if you want (trans in neutral, clutch dis-engaged) but why?

If you have a Ford/Mazda M5OD-R1 or R1HD transmission, the extra wear on the pilot/throwout bearing doesn't matter: you'll probably have to tear it all apart to replace the throwout cylinder before either wears out anyway.
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Old 03-12-2019, 10:49 PM   #15 (permalink)
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Quote:
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The bigger question here: Is the throwout bearing SPINNING when the engine is off, which I think it is not, in which case you can hold it down for as long as you want as long as the engine is off. I would definitely be shifting to neutral for a 5 minute coast though.
Good point, I was thinking of engine on idling, such as most people will do at red lights. A lot of folks just hold the clutch in and this causes wear on the throwout bearing and spring.

But even with the engine off you're holding tension on the spring, and your leg, neither of which is necessary.

I've done a fair bit of EOC in the past when I was broke as a joke and running on fumes, and never had issues getting the trans back into gear while rolling with the engine off.
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Old 03-18-2019, 10:55 PM   #16 (permalink)
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Quote:
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In either case, if you put the transmission in neutral, the input and output shafts will soon be rotating at different speeds. Re-sycing them to get into gear will require the syncros to do work matching the speeds, unless you start the engine first and do rev-matching. If you want to bump start, you either need to leave the transmission in gear or use the sycnros.

So, for EOC, you can choose: syncro wear (trans in neutral, clutch engaged) or leg pain and throwout/pilot bearing wear (trans in gear, clutch dis-engaged). You can do leg pain AND syncro wear if you want (trans in neutral, clutch dis-engaged) but why?
No wear bump starts.

The engine is off so zero rpm. Push the clutch down for ~5seconds and the input shaft will slow to zero rpm too. 0+0= zero wear. That's what I have to do with my non-syncro truck. If you don't wait for the input shaft to stop to it will just crunch.

If you can't wait for 5 seconds before bumping, just barely touching any gear will stop the input shaft immediately. Then select the gear you want, just going into gear immediately causes about twice the wear going by feel.

I usually touch 4th to stop the input shaft, then shift into 5th. If sometimes I need to bump fast I just go straight for 5th. That way I'm spreading any wear over two syncros. While accelerating I often skip 4th so that's my 'sacrificial' syncro.

But where possible, I use the 5 second no wear trick.

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