[grahamp]

Ratio on the window sticker was 3.55. I think the replacement is a higher ratio and closer to 4.00 since the rpms are very busy! This is what prompted me to take a closer look at the rear end. I tried to calculate by counting the prop shaft turns to one turn of the tire, came out as two to one which is certainly not accurate! Probably because I have a posi unit and had the other tire on the ground , I think both tires have to be free to turn? So will try that, and in extremis, I will remove the differential back plate

[LPete]

Just throwing this out there, but with a regular posi you shouldn't be able to turn the driveshaft with one wheel on the ground. If you can it means the posi isn't working.

Originally Posted by grahamp

Ratio on the window sticker was 3.55. I think the replacement is a higher ratio and closer to 4.00 since the rpms are very busy! This is what prompted me to take a closer look at the rear end. I tried to calculate by counting the prop shaft turns to one turn of the tire, came out as two to one which is certainly not accurate! Probably because I have a posi unit and had the other tire on the ground , I think both tires have to be free to turn? So will try that, and in extremis, I will remove the differential back plate