Need help. I have a 1972 GS 455 without posi. Can someone tell me the exact location of the code. I just spent thirty minutes with a wire brush (explanation for title) and cannot locate any code on the tube. How big are the markings, are they stamped or raised? I believe I have 3.42 gears. Any help would be greatly appreciated. Thanks in advance for any help. Scott Mc

There's been some discussion on this and it seems the markings were often very light or not there at all. It looks like the only real way to know is open it up. Have you been to George's site? www.buickperformance.com He has a good picture of a ring gear and what to look for on it.

thanks for the info. I checked out the site. I really enjoyed the pix of everyones cars. I was hoping to find out the gears with out opening it up. Thanks again Scott Mc

If your good at math You can get a real close estimate by figuring out the Dia and travel of the tire for one rotation and then figure in how many times the drive shaft turns. Helped a guy do it once. He marked the tire and I pushed the truck so the tire turned one time, and he counted the times the drive shaft turned. Some reason you gotta leave the vehicle on the ground with a peg leg to get an accurate count.

Jack one rear tire off the ground leaving the other one on the ground. Then mark both the tire and the driveshaft. Put the trany in neutral and turn the tire 2 complete revolutions and count the turns of the driveshaft. If it goes around 2 1/2 times you have a 2.5x ratio. If it goes around 3 1/2 times you have a 3.55 ratio. :Smarty: You can get a real good idea the ratio by doing this. :beer Mike

Note. This is exactly how to do it with the non-posi as stated! If your reading this and you have a posi, then the formula changes to both tires off the ground and one rotation of the wheel.

Agreed. I looked all over my 71 axle tube and could find no codes. The quicker/simpler method is to count the revolutions as mentioned. Good luck.

Best solution to figure out the ratio & the condition (to some degeee) of what is inside, is to pull the rear cover, drain the grease & look at the numbers stamped on the ring & pinion. Most folks neglect changing the grease in their differentials. Often its time for a good flushing & refilling! :3gears: Roger