On a CAR, fellas.

Anyway, the number I got from my '72 Chevelle is 3969277NF. Can anyone tell me what the gear ratio is?

BTW-This probably isn't the right forum, but we don't have one for rears.:D

Marci,

I cant find anything on 72 rearend codes... even this site doesnt have rear codes for 72! I dont believe it!

Guess its time to get dirty. Pull the cover and count the teeth on the ring gear then divide that number BY the number of teeth on the pinion.

Bubba

That is the casting number for a 70-72 10-bolt rear. There should be a code stamped into the front of the passenger side axle tube in the format CCA1025B or something similar where CCA is the ratio code (3.36 non-posi 10-bolt in this case), 10 is the month (October) of assembly, 25 is the day of the month and B (Buffalo) is the assembly plant. Keep in mind this is just an example and yours will most likely not be the same.

Like David sad, look on the front of the passenger side axle tube and post that number here.
If you can't find or read it, there's another way of finding out:
Lift the rear up and put the frame on jackstands. Put the tranny into neutral, be sure to secure the front wheels so it can't roll away. Turn a wheel and see in which direction the other wheel is turning, if it's turning forward, you have a Posi. If it's turning reverse you'll have to lower the other side so the wheel has contact with the ground and can not turn. Then mark your driveshaft and your wheel and turn the wheel so the driveshaft makes one full revolution. Count how many times you had to turn the wheel. That's your ratio.

Olli

More than likely a 2.73, if someone hasn't changed the gear. All I have seen are 2.73 in '72 in a 10 bolt.

I found the right #!!!! It's GCC 246 2 I know it was built on the 246th day of the year, in Buffalo. (i think) Anyway, I'm mostly interested in what the ratio is. Does anyone know?



It doesn't look like it will be right for a 700R4 tranny.......

GC is 2.73 open and C is Buffalo.,
sorry I had CG the first go round ,still the correct 2.73 though.

I'll add another one to my list!

Here's where I found my ratio. Great site to decode everything chevelle.



http://www.chevellestuff.com/generic/quick_decode_links.htm

Here's where I found my ratio. Great site to decode everything chevelle.

http://www.chevellestuff.com/generic/quick_decode_links.htm

:D Thanks, nice to know it's helpful.