Rear Axle Ratio on a 41' Plymouth coupe ?

Need help with the ratio on this rear end ?...

Thanks

Jason Lee-

 

I am not sure this works, but make a chalk line on the driveshaft. Jack one wheel in the air and spin it 360 degrees while counting how many times the driveshaft spins a full turn before the wheel makes it all the way around.

If you have a little more then 4 turns ...its a 4:10
If you have a little more then 3.5 turns ...its a 3:73

 

Ring gear grooves divided by pinion grooves equals ratio..

 

The axle is in the car with no drive shaft

 

You need to go two turns of the wheel exactly, to count the driveshaft yoke turns. The other wheel needs to be on the ground or not moving at all.

 

Bingo!
The reason you do two full turns is to compensate for the reduction thru the differential. If the rearend were a Posi, you would need to jack both wheels off the ground and just rotate the wheels once (together) as the Posi has clutches to keep the diff from working under light loads.

No shaft...mark the yoke that the shaft attaches to.

 

Thanks guys !