I bought the jeep the way that it is so I don't know what may have been done different than stock. I did spin one side and the other side was stationary. I didn't know that would have an effect on the ratio. Tire diameter is 31inches. I currently have the transfer case in pieces because I am doing a slip joint eliminator. Had to order a complete rebuild kit when I found what I found inside. Oil appeared to be contaminated and it looked like it hadn't been completely rebuilt since it was new. When it was running,, the speedometer was indicating about 5mph too slow at highway speeds. So, I figured I would do a gear change in the speedometer pickup to correct the odometer. The odometer gear change requires gear ratio of the rear end and tire size to figure out what gear for the sender.