Determine gear ratio turn input count revolutions axle flange?

[Shoepop]

I have a 901 7:31, I know the gears are not stock. I marked the input shaft and axle flange. With the trans in 5th gear it took 13.75 revolutions of the input shaft to make one revolution of the axle flange. Can anyone provide me with a formula that I can use to deterime 'approximately' what the 5th gear ratio is? I'm aware this is crude, only trying to get close. Thanks

[Bill Verburg]

you divide that # by the cwp ratio

7:31 is 4.42857....

so 13.75/4.42857 = 3.10

i.e. it looks like a stock 901 A 1^st A is 3.091

[Shoepop]

Got it, thank you Bill. I was backwards thought I was in 5th but was in 1'st With formula you provided I came up with a U 5th.