Differential Info
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Le Mans Master
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Differential Info
Just bought a 3.36 rear end and would like to know what I got. I tried googling the codes but couldn't find anything revelant. The cast iron info is (as best as I can tell):
B287
GM 23
3725899
Can someone decipher this, please?
B287
GM 23
3725899
Can someone decipher this, please?
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From: Shamong, NJ
I'd say that the B287 is February (B) 28th, 1957. 3725899 is the casting number for the 57-61 open (non posi) rear end center section. If it had been a posi carrier it would be casting number 3743833.
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Le Mans Master
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Over on the OTHER side of the case, there will be (or should be) STAMPED letters/numbers. It will begin with TWO letters followed by 3 or 4 numbers. The letters are the ratio code, the numbers are the mo-day of actual assembly.
Here are a couple of examples.
Here are a couple of examples.
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Le Mans Master
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Yes, I found the letters/numbers DZ, but they are very lightly stamped, hard to read. Best I can tell is BL 314. What does that translate to?
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First of all, are you sure the 7 in B287 is a 7? Could it be a 1?
Next, I cannot find ANYTHING remotely close to a BL stamping except for a 4.11 3spOD in a pass car. The 314 is an assembly date of Mar 14 (which would follow the CASTING date of B28, which is Feb 28).
Take another close look at the stamped letters (BL). Some assembly line workers struck the stamp lightly while others stamped them very hard.
And last, are you sure the gears are 3.36? If so, I'm wondering if someone replaced original 4.11 gears with a 3.36 gear set.
Next, I cannot find ANYTHING remotely close to a BL stamping except for a 4.11 3spOD in a pass car. The 314 is an assembly date of Mar 14 (which would follow the CASTING date of B28, which is Feb 28).
Take another close look at the stamped letters (BL). Some assembly line workers struck the stamp lightly while others stamped them very hard.
And last, are you sure the gears are 3.36? If so, I'm wondering if someone replaced original 4.11 gears with a 3.36 gear set.
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Le Mans Master
Joined: Apr 2013
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From: Arlington TX
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First of all, are you sure the 7 in B287 is a 7? Could it be a 1?
Next, I cannot find ANYTHING remotely close to a BL stamping except for a 4.11 3spOD in a pass car. The 314 is an assembly date of Mar 14 (which would follow the CASTING date of B28, which is Feb 28).
Take another close look at the stamped letters (BL). Some assembly line workers struck the stamp lightly while others stamped them very hard.
And last, are you sure the gears are 3.36? If so, I'm wondering if someone replaced original 4.11 gears with a 3.36 gear set.
Next, I cannot find ANYTHING remotely close to a BL stamping except for a 4.11 3spOD in a pass car. The 314 is an assembly date of Mar 14 (which would follow the CASTING date of B28, which is Feb 28).
Take another close look at the stamped letters (BL). Some assembly line workers struck the stamp lightly while others stamped them very hard.
And last, are you sure the gears are 3.36? If so, I'm wondering if someone replaced original 4.11 gears with a 3.36 gear set.
Yes, it is a 3.36, 11 on the pinion, 37 on the ring.
one
two
three
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OK, absolutely, positively, that is a 57 rear.
Now, here is the closest thing I can come up with (thought I had it). That could be BB (weak stamp), which translates to 3.36 for a 57 pass car with PG or TG. BUUUUUUUT, that does not fit, because your rear is a Detroit Gear and Axle built rear, and a BB code is ONLY for a Buffalo (NY) plant.
So, I give up.
Anyone else want to take a shot at it?
Now, here is the closest thing I can come up with (thought I had it). That could be BB (weak stamp), which translates to 3.36 for a 57 pass car with PG or TG. BUUUUUUUT, that does not fit, because your rear is a Detroit Gear and Axle built rear, and a BB code is ONLY for a Buffalo (NY) plant.
So, I give up.
Anyone else want to take a shot at it?
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Thread Starter
Le Mans Master
Joined: Apr 2013
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From: Arlington TX
2024 C1 of the Year Finalist - Unmodified
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OK, absolutely, positively, that is a 57 rear.
Now, here is the closest thing I can come up with (thought I had it). That could be BB (weak stamp), which translates to 3.36 for a 57 pass car with PG or TG. BUUUUUUUT, that does not fit, because your rear is a Detroit Gear and Axle built rear, and a BB code is ONLY for a Buffalo (NY) plant.
So, I give up.
Anyone else want to take a shot at it?
Now, here is the closest thing I can come up with (thought I had it). That could be BB (weak stamp), which translates to 3.36 for a 57 pass car with PG or TG. BUUUUUUUT, that does not fit, because your rear is a Detroit Gear and Axle built rear, and a BB code is ONLY for a Buffalo (NY) plant.
So, I give up.
Anyone else want to take a shot at it?