Question about downshifting MS3, double-clutching needed?

[DailyDriver]

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[Stavesacre21]

lol, sorry for the long explanation...btw, if I sounded at all attacking or rude I didn't mean to be

I didn't take it that way at all lol. I actually had seen similar illustrations, and for loss of any explanation off the top of my head, found to to be exactly what i'd heard before.

I've had 2 T-45 trannys replaced in Cobras, so i've seen just about everything there is. I found it to be a rather well-worded explanation.

As you know, there just isn't any shortcuts when trying to understand something like a tranmission. Compared to what i heard, that was a cliffnote version anyway.

(dance)

 

[Olestra]

Great post by neox.
He explained what many have failed to explain or understand.
Whether you're engaging the clutch or not while in first at 20mph is irrelevant since it is after the fact.
Alot of people think that clutch in with the gear lever in first is the equivalent of neutral, when it is not.
To summarize neox in one sentence, downshifting the lever into first gear while you're traveling at 20mph, causes wear on the synchros and especially if you're forcing it in.

Daily Driver, I have developed this habit that you speak of except I only try to put the lever in first as the car is crawling at walking speed. Still, I will experience the lockout feeling from time to time, but I find if I blip the throttle, the shifter often goes in without any grinding or resistance. I also find that moving to 2nd and then to 1st, all while the clutch is disengaged (pressed down) helps as well.

 

[xX StitcH]

the gears on the layshaft are directly attached to the layshaft, and spin at the engine's speed at all times

Excellent post, however I'm pretty sure this part is incorrect. If the clutch is disengaged (i.e. your foot is holding the pedal down), the engine is not connected to the transmission. You should have said, the gears on the layshaft are directly attached to the layshaft, and spin and the same speed as the clutch disc.

 

[harrisonchang]

Why would you shift into 1st while moving? You should never shift into 1st while moving.

 

[xX StitcH]

Alot of people think that clutch in with the gear lever in first is the equivalent of neutral, when it is not.

Thank god there are some people who understand how a transmission works.

To expand on that, if you force the transmission into first while going 20mph with the clutch disengaged, the clutch disc is spinning at just under 4,000 rpm regardless of engine speed (this is true for the 2.5L MZ3, I'm sure the gearing for the speed3 is different).

There was a discussion awhile ago about someone putting their car into first while going around 55 mph. That would make the clutch disc spin at ~10,500 rpm!!! Talk about a terrible idea, **** the syncro and possibly have the clutch disc explode.

 

[Olestra]

Why would you shift into 1st while moving? You should never shift into 1st while moving.

No, you can downshift into first if done properly and you're moving slowly enough, so I wouldn't say never, but in practicality, it's difficult due to the high gear ratio and you can usually get away with 2nd gear.

 

[not yellow]

i do a lot of city driving and shift into 1st while going less than 10mph all the time. never a problem and gives me much more responsiveness on acceleration. but anything above 10mph is super rough on the transmission...