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Old 10-28-2017, 06:40 AM   #1
rer_239
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Default differential questions new

i'm back! bought a rear axle (cheap) had to replace the axle shafts and housings. found better housings and shafts. my first axle had a 37 tooth ring and a 9 tooth pinion gear. the better shafts came assembled with the carrier assy and spider gears. but it had a 34 tooth ring gear. can i use just the better axle shafts? according to Tom Endy both 34 and 37 ring gears used a 9 tooth pinion gear. does that mean that the 9 tooth pinion gear will work on either ring gear. i planned on using 16" wheels on a stock chassis/drive train and wanted to end up with a car capable of 50 mph with out overenxtending the engine (approx 2000 rpm). the 37/9 combination w/16" wheels (i think) ends up with 2400 rpm @ 50 mph. the 34/9 combination would lower rpms to approx 2200 rpm.
first question can i use just the better axle shafts
second question will both ring gears (37 and 34 tooth) work with the 9 tooth pinion gear.
whew, sorry about the rambling.
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Old 10-28-2017, 06:45 AM   #2
Floats
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Default Re: differential questions new

Rer,
I think the cut of the gears are different. Check if they mesh correctly before installing.
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Last edited by Floats; 10-28-2017 at 07:43 AM.
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Old 10-28-2017, 07:32 AM   #3
Railcarmover
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Default Re: differential questions new

The pinion tooth profile will be different,do as Floats says,fit the gears before doing anything else..
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Old 10-28-2017, 07:59 AM   #4
rer_239
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Default Re: differential questions new

Ok that makes sense
Thanks
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Old 10-28-2017, 12:41 PM   #5
Tom Endy
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Default Re: differential questions new

The 9 tooth pinion gears used on the 378 and 411 are not the same size. One is smaller than the other. The 411 9" is smaller in diameter. It would appear that they are not interchangeable.

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Old 10-28-2017, 01:59 PM   #6
Charlie Stephens
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Default Re: differential questions new

Even if they would work you should always use ring and pinion gears that are matched sets.

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