Rear end identification.

On my rear end the numbers read ON 051 then there is another space then it has N 051

So it looks like this ON 051 N 051 ( on the driverside)

What could this be? I dont see any B or anything that could tell my what type of rear it is.

I used the Help sheet posted on atlantabuick but I think I am missing a letter. or I thought it should have AD B then date code, or something similar.ou: ou:

 

ON shows as a 3.64 posi rear in a '69 GS400 & '70 GS455,both with standard shift trans..

 

Steve is correct. I have attached a chart that may help you. Make sure you zoom in to read it The "ON" looks like an "OW" in the chart but it is "ON"..

 

So it is safe to assume that I do have a buick rear end.

 

Buick rearend yes, but it loks like you have a rear out of a stickshift car. Auto cars came with either a 2.93 or a 3.42.
Does your car rev pretty high when you are doing like 65mph? If so it still might have the original 3.64 gears in it.

 

Sure does.

What is that equation people use to figure out the gear ratio??

 

Just jack the car up and spin the rear tire once (by hand p ) while counting the number of times the drive shaft turns. This sould get you close idea...

 

My wife said that my days of trying to identify rear ends is over :ball:

 

Automatic trans Non AC 69-70 GS Stage 1 cars also came standard with ON 3:64 Posi axle not just 4 speed Stage 1's.

 

WHat's really intersting is I have an LB code on mine which would normally be 2.93 open. But since my car was built in Canada it has 3.08. I counted the teeth 3 times to make sure. Then I heard several people on this board say this is fairly common in the Canadian cars.

 

Ken since your car was Canada built does it have a 12 Bolt Chevy in it? So far the 69 Canadian cars I have seen have had the 12 bolt.
The Canadian built GS that my brother has had a 12 bolt chevy and 3.31 gears

 

Here is a link of the Canadian 12 bolt decode for the GS.

http://www.v8buick.com/showthread.php?t=87932&highlight=canadian

 

Yes, it is the 12 bolt pegger. :TU:

 

That's interesting. I thought mine said LB, but now I'm not sure if it said LB or LD (Canadian). Actually, my gears work out to be numerically 3.07, which was the ratios Canada used according to that cool chart you linked to. So it is a 12 bolt and they are 3.07's, but the code I'm not positive if now if it's LB or LD. Should be LD according to the chart, but I wouldn't be surprised with QC back in those days if it's an LB stamped rear. :error: .