my car has aftermarket gears from the previous owner andi dont know what they are....stock is 2.73.

For every 3.5 (a little over that) times i turned my driveshaft, the tire made one complete rotation. How do i find out my gear ratio? Am i going at this the right way? The wheel and tire combo is stock also (245/50 16in)

 

My guess would be 3.73.

You could also try the Tech Equations. AT -> https://www.thirdgen.org/newdesign/t...ulations.shtml


From that you should beable to take RPM, MPH and Tire Size and figure the total gear ratio then use that to pull out your tranmission gear ratio which will give you your rear end gear ratio.

Course still that's just approximations, if you wanted to do it the dirty way count the teeth on the ring and pinion.

 

You need to take off the cover and look.

You just bought the car; one of hte first things you should be doing, is changing all the fluids. That would of course include the rear end grease. Changing that requires removing the cover. While you're catching up on that little detail of necessary work that you should have already done, make a point of observing the gears.

 

ok ive had the car since June....

i had the rear diff fluid changed by JIffy Lube today (yes i got in the pit and watched them and made sure they did it right). I have no intrest in pulling off the cover and making another gasket and messing with it just to find out what gears it has.

it turned a bit over 3.5 times so i'd say 3.73's is a good estimate

the car has a digital speedometer calibrator so i cant do any calculations that involve speed


3.73's omg thats way to tall for a 305 tpi