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» www.chirpthird.com » SSOA and friends » SSOA: "Back Porch" » Dropping to 3rd at 60-65mph...grind...anyone know why this happens?

   
Author Topic: Dropping to 3rd at 60-65mph...grind...anyone know why this happens?
Machine
1st Gear
Member # 1138

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Just about every time I try to drop to third when I'm cruising around 60-65mph, it grinds when I put it into gear. I really don't know much about transmissions/synchros, so I'm looking for a little guidance. Should I just ignore this and not worry about it?

I've tried it with the clutch fully engaged both at high RPMs and low RPMs. Same result either way. I usually try to run the RPMs up to 4500-5000 when performing the shift.

3rd should be good to 100mph.

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Posts: 43 | From: Lombard, IL, USA | Registered: Aug 2001  |  IP: Logged
DaddySS
Old Coot.....50 going on 20
Member # 848

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I assume if you double clutch it does the same thing? In short, the synchros have to match the drive gears to the speed of the driven gears and help to line up the teeth so the two gears can mesh. If they are grinding it is because the synchros haven't been able to match the speed in time for you to shift. Double clutching, shifting slower, and helping to match the speed by, in this case, by raising the rpms, all should help. If you do all of that and they still grind, you may just have a bad synchro.

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Posts: 3403 | From: Woodcliff Lake, NJ, USA | Registered: Dec 2000  |  IP: Logged
Machine
1st Gear
Member # 1138

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Actually, DaddySS, I've never double clutched. I thought double clutching was only used with special racing transmissions. I will try that next time. Thanks!
Posts: 43 | From: Lombard, IL, USA | Registered: Aug 2001  |  IP: Logged
Dante
1st Gear
Member # 1429

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That sure sounds like the problem I had years ago with a M-21 four speed; and it turned out to be the synchros for the first two gears. Good luck!

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Posts: 60 | From: Ellicott City, Md. | Registered: Mar 2002  |  IP: Logged
HotWheelSS aka HTWLSS
SSOA Director
Member # 117

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Sounds like you might want to have someone take a look at that while it's under warranty.

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Posts: 7198 | From: Near Portland, Oregon, USA | Registered: Feb 2000  |  IP: Logged
Machine
1st Gear
Member # 1138

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I thought about that, but I don't know what any dealer would think about this manuever. It's an awfully aggressive shift.
Posts: 43 | From: Lombard, IL, USA | Registered: Aug 2001  |  IP: Logged
   

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