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Old 06-17-2010, 12:05 AM   #1
64c10stepside
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Low rearend gearing with a granny gear trans

Has anyone ever looked into running a real low gear ratio in the rear end so the the granny gear functions as a real 1st gear and the top gear would be an overdrive??
Is this possible?
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Old 06-17-2010, 12:45 AM   #2
apachedaddy
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Re: Low rearend gearing with a granny gear trans

It would work but you would have to run a real high 2:?? or low 3:?? to get there. That also means changing out your carrier to take that high of gear.
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Old 06-17-2010, 01:32 AM   #3
Captainfab
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Re: Low rearend gearing with a granny gear trans

The one problem with that is I don't believe there is a synchro on 2nd gear, so it will grind everytime you shift from 1st to 2nd. I could be wrong though....

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Originally Posted by 64c10stepside View Post
Has anyone ever looked into running a real low gear ratio in the rear end so the the granny gear functions as a real 1st gear and the top gear would be an overdrive??
Is this possible?
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Old 06-17-2010, 04:48 AM   #4
raycow
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Re: Low rearend gearing with a granny gear trans

Second gear is synchro on the SM420, so no problem shifting on the fly. Actually, you won't be using first gear very much anyway, even with the taller rear gearing. Second on the SM420 is lower than first on the 3 speed.

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Old 06-17-2010, 10:48 PM   #5
Captainfab
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Re: Low rearend gearing with a granny gear trans

What about in the SM465?

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Originally Posted by raycow View Post
Second gear is synchro on the SM420, so no problem shifting on the fly. Actually, you won't be using first gear very much anyway, even with the taller rear gearing. Second on the SM420 is lower than first on the 3 speed.

Ray
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Old 06-17-2010, 11:07 PM   #6
raycow
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Re: Low rearend gearing with a granny gear trans

Second and third are roughly the same on the 420 and 465 (about 3.5 and 1.7 respectively). First is slightly taller on the 465 (about 6.5 vs 7.0). I have a page bookmarked somewhere with the actual ratios and if I can find it I will post it.

Ray

Last edited by raycow; 06-17-2010 at 11:07 PM.
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Old 06-17-2010, 11:31 PM   #7
raycow
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Re: Low rearend gearing with a granny gear trans

Ok, found it.

http://members.cox.net/jeepinrandy/r.../transinfo.htm

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Old 06-17-2010, 11:36 PM   #8
Captainfab
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Re: Low rearend gearing with a granny gear trans

Is 2nd gear on the SM465 synchro'd the same as the SM420?
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Old 06-18-2010, 12:05 AM   #9
raycow
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Re: Low rearend gearing with a granny gear trans

Yes, the 465 has synchro on 2nd. Sorry, I didn't realize that was what you were asking about the first time.

Ray

Last edited by raycow; 06-18-2010 at 12:09 AM.
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