Question about a 9" rearend

28RPU

28RPU

Senior Member
I just got a 9" rearend out of a 57 Ford.I am not to knowledgeable about rearends so I have a question. WIth it lying on the ground with no wheels or weight on it,I can turn the pinion but neither axle shaft will turn.I can turn either axle but the pinion or the other axle won't turn. I assumed it had a stripped gear so I pulled out the chunk and no visible damage is there.Axel shafts are good.The pinion and ring gear are good and smooth so do I assume the spider gears are bad or is this the way its supposed to work?I don't see how this could be right. :confused:
 
If its not a posi rear, one side will not usually turn if the other side is rotated. Chunk? - I always heard it being a "chuck". Guess here are a lot of different names for the center section, pumpkin, etc. LOL
 
Neither axle will turn,nor will the pinion turn whenever I turn the other.They all turn freely and independently.Nothing seems to be connected to the other but I see no damage internally.
 
Spider gears are gone or the spider gear pinion shaft is sheared/missing allowing the gears to rotate within the housing.
 
28RPU said:
Neither axle will turn,nor will the pinion turn whenever I turn the other.They all turn freely and independently.Nothing seems to be connected to the other but I see no damage internally.
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If you lock one axle and turn the pinion the other axle should turn.Divide the small # of teeth into larger gear and get ratio.
 
With the center section out, you should be able to see the spider gears. You can slide the axles back into position in the center section, hold one side, rotate the other and see what is going on in there.
 
Thanks for the input.Guess its time to tear it all apart and rebuild it or just get another one.
 
28RPU said:
Thanks for the input.Guess its time to tear it all apart and rebuild it or just get another one.
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Do not listen to those who said there is something wrong because the other axle does not turn (in a ford 9 inch) if you turn the other side. This is perfectly normal unless it is a posi rear - then both axles should turn.

This is not to say that they won't turn. If everything is sticky (oil) enough inside then the other side will turn, in the reverse direction if I remember correctly.

One way to get find out the ratio of the rear in a non posi rear is to make sure that one wheel is touching the ground before spinning the other axle.
 
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I reread your thread and have to change some of my comments. If by turning the pinion neither axle moves, then you have problems, probably bad spider gears.
 
Did someone maybe put the wrong axles in at sometime?
If they are too short to engage the side gears ,it may appear that your diff is bad when it isn't.
I have seen it happen before.
 
burnin53 said:
Did someone maybe put the wrong axles in at sometime?
If they are too short to engage the side gears ,it may appear that your diff is bad when it isn't.
I have seen it happen before.
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I have too, but the '57 Ford (car) 9" is the narrowest rear Ford made. So the shafts would have had to be cut or custom.

I would either put wheels on, to hold the shafts tight to the ground, or wedge a crowbar to lever against the ground, and then turn the pinion. If the pinion still turns freely, then it's obvious something's wrong.... whether limited slip or open.
 
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