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Discussion Starter · #1 ·
I have a Ford 9" nodular case rear end in my '37 Ford that has started making noises. I only have about 1600 miles on the car and everything was new, Auburn limited slip, 4:11 gears, Bear axles etc. I've been getting a metallic clanking noise when coming to a stop (just one clank, not repeated) and then after about 1200 miles it's developed a whine. The whine is only under acceleration and is totally silent when cruising or letting off the throttle. I'll end up pulling the pumpkin out to check it, but curious to see if anyone can diagnose it from the description. Thanks, Bill
 

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Are the rear tires exactly the same size with the same amount of tread wear and exactly the same air pressure? If not then you are causing problems with the Auburn trying to slip. The Auburn would have been just about my last choice for a differential, but since you already have it then add another bottle of limited slip oil additive to it and see if it gets any better. If the tires are not exactly right then you are putting a lot of heat into the oil and probably causing yourself trouble.
 

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The whine/quiet changing with load sounds like a loose pinion. If something changed on the crush collar the pinion will move as load changes. The clanking may well be the posi unit as Biggearhead mentioned.
 

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Discussion Starter · #4 ·
Are the rear tires exactly the same size with the same amount of tread wear and exactly the same air pressure? If not then you are causing problems with the Auburn trying to slip. The Auburn would have been just about my last choice for a differential, but since you already have it then add another bottle of limited slip oil additive to it and see if it gets any better. If the tires are not exactly right then you are putting a lot of heat into the oil and probably causing yourself trouble.
Yes, tires are the same size, pressure and overall height. I had a Detroit Locker that made a similar clank, but it only did it on tight turns. I'll try another bottle of friction modifier, but not holding out much hope.
 

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Discussion Starter · #5 ·
The whine/quiet changing with load sounds like a loose pinion. If something changed on the crush collar the pinion will move as load changes. The clanking may well be the posi unit as Biggearhead mentioned.
I'm thinking crush sleeve as well. I didn't assemble the centre section, but if it is a crush sleeve, I may change it to shims.
 

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the clunk in decel is probably the trans downshifting, if automatic. Check for any movement in the suspension components, check the torque on all the links.
the whine is much harder to fix and is probably inherent in the gear set.
 

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Discussion Starter · #9 ·
the clunk in decel is probably the trans downshifting, if automatic. Check for any movement in the suspension components, check the torque on all the links.
the whine is much harder to fix and is probably inherent in the gear set.
It is an automatic, 700R4 and is a definite metallic clank, like if you hit a steel pipe with a hammer kind of noise. I'll pull the centre section our in the next few weeks and check it out.
 
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