How can you tell if the 5 speed dual gearbox has a final drive ratio of 3.7 or 3.9.?? it is out of a RX 

Hi This is Jerry, count the splines on the axle shalf if it's 23 it's got 3.90 gears if it has 25 it's 3.70 gears also you said it's out of a rx that has 25 splines 3.70 gears. Thanks Jerry

Hi This is Jerry, count the splines on the axle shalf if it's 23 it's got 3.90 gears if it has 25 it's 3.70 gears also you said it's out of a rx that has 25 splines 3.70 gears. Thanks Jerry

 

There are also S/R 5spds from Non-turbo XTs that have 23 spline, but 3.7 ratio.  So the stubs don't concretely tell.....but in most cases yes.

 

This trans from an RX should be 25 spline and 3.7