Transmission & Drivetrain Gearboxes, Differentials, Clutches

DC2R gear box notchy

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Old Jul 15, 2019 | 04:56 AM
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Default DC2R gear box notchy

Hi all

I have an AUDM 2000 DC2R with 120k KMs (74k miles) that sometimes feels very hard to slot in when downshifting to 3rd from 4th only when cold. Once the car warms up or in hot weather this does not happen. All other gears are fine and the car is in prestine condition as it is only driven once every 2 weeks.
I have recently changed the gearbox oil but it still happens.
Is this normal in cold conditions? Or could it be the box or clutch cylinder?

Last edited by mr_munro; Jul 15, 2019 at 05:05 AM. Reason: Title
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Old Sep 8, 2020 | 09:25 PM
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Default Re: DC2R gear box notchy

bumppp
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Old Sep 8, 2020 | 10:05 PM
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Default Re: DC2R gear box notchy

Maybe the rubber in the shift linkage bushings is drying out. So it's not actually the gearbox, but the linkage.
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Old Sep 9, 2020 | 09:06 PM
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Default Re: DC2R gear box notchy

Check your clutch master cylinder and slave cylinder... and make sure that the line is properly bled between the two.
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Old Sep 10, 2020 | 03:08 AM
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Default Re: DC2R gear box notchy

Thanks all
Also forgot to mention when it does go in, it will grind, again only when cold
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Old Sep 14, 2020 | 08:08 PM
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Default Re: DC2R gear box notchy



Synchros going out more than likely. If it only does it when cold, its prob not a bent shift fork. The shift fork fits in the slot between 3rd and 4th (well, the one we are questioning does) on the mainshaft (mainshaft goes to clutch). When you downshift from 4th back into 3rd, that collared slotted ring, is moving from right to left. The gold colored synchros have friction material on the inside diameter, that engages and disengages as the slotted ring moves towards or away from it. It is "syncronizing" the RPM difference between using the 3rd and 4th gears. Youre in 4th, push clutch and shift to 3rd; collar slides left, the synchro on the left starts to engage, which speeds up the RPM of the mainshaft, before finally locking into 3rd gear. Which in turn brings your RPMs up when you reengage the clutch. If the synchro doesn't engage enough because the inner diameter friction material, or the outside teeth on it are worn out, the RPMs wont match like you want them to, and it won't want to finally lock in to 3rd. That's why if you don't let off the clutch, put it in neutral, and bring your rpms up manually, it will slide right into 3rd if you do it right. You are increasing the RPMs of the mainshaft with the throttle, and doing the job of the synchronizer.

It's more than likely the synchro on the far left side of the mainshaft that is giving you problems. 3rd gear one

Visual of it @ 3:45 :

Image came from this great thread:
https://honda-tech.com/forums/transm...orial-2443459/

Last edited by full Circling; Sep 14, 2020 at 10:17 PM.
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Old Oct 26, 2020 | 02:17 PM
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Default Re: DC2R gear box notchy

would you know the part number for the synchro ?
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Old Oct 26, 2020 | 07:03 PM
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Default Re: DC2R gear box notchy

Here in the USA, you cannot purchase the 5th gear synchro by itself... it is only available with the 5/R sleeve set. Synchrotech sells brass synchro rings individually.
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Old Oct 26, 2020 | 07:08 PM
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Default Re: DC2R gear box notchy

Originally Posted by JRCivic1
Here in the USA, you cannot purchase the 5th gear synchro by itself... it is only available with the 5/R sleeve set. Synchrotech sells brass synchro rings individually.
its 3rd I need, and ill be purchasing from https://www.amayama.com/en
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