gearobox internal ratio

[DCM]

my old brain can't remember how to calculate the IR of a 2wd gearbox... can someone remind me??

[Jamesy]

You need to devide the number of teeth on the diff gear by the number of teeth on the top shaft gear.

[DCM]

ok, thanks, wasn't sure whether you have to take into count the idler gear

[Jamesy]

As the idler gear is driven by the top shaft gear and then drives the diff gear it gets cancelled out in the calculations.