C-3 Rear Gear

[John D.]

My 68 is supposed to have a 3.70 to 1 ratio. Any way to check the ratio without pulling it apart?

Thanks, John D.

[Jack H.]

Re: C-3 Rear Gear

Yes, in fact with these cars as old as they are typically having gone through multiple hands, I advise testing to confirm exactly what ring/pinon setup is actually 'living' inside the rear end today!

Get the rear tires off the ground (preferably on a lift). Put a chaulk mark on the drive shaft and one on the tire. Slowly/carefully rotate the marked rear wheel and count the number of rev's it takes to get the drive shaft to spin once. You'll empirically determine the rear gear ratio (4.11:1, 3.55:1, Etc.).

[John H.]

Re: C-3 Rear Gear

The 3.70 was available in both open and Posi versions in '68; if it's "open", the wheel on the other side will turn in the opposite direction when you turn one side. In this circumstance, have a helper turn the other wheel one full turn as you're doing the same thing on your side. If it's a Posi, turning one side will also turn the other side in the same direction.

[Jim T.]

Re: C-3 Rear Gear

What letters did you find stamped on the unit?

[John D.]

Re: C-3 Rear Gear

1AO1067

AO = 3.70 posi

Build date 10/6/67

1st shift

Right?