1993 Toyota 4runner 4x4. I Have a blown out rear diff so I want to know the gear ratio in my axles in order to pickup a used rear axle. G254- 4.56 according to VIN but want to spin the tire test for know sake to be sure. Cant spin my rear tires due to missing pinion teeth. My question is can I disconnect the front 4wd driveline at the flange being sure to mark where it connected and spin a tire 20 times to get my gear ratio?


One more question if I spin my front axle tire 20 times but my transfer case has not moved the rear diff will this mess up my truck once I reconnect the driveline?

 

You blew the rear diff so it has to be replaced.
Pull it and count the ring gear teeth and divide by pinion teeth.
The spin the tire method is kind of subjective .

 

Won't mess up your driveline.....just don't let the driveshaft come apart at the slip-splines.....if you do intend on letting it slip apart then mark them so they re-spline the same place.

4.56 gears are factory color coded yellow.....do you see some yellow paint on the pinion nut?


If the front has manual hubs then engage them then you can jack 1 side off the ground and spin the tire 1 exact full revolution and see if the driveshaft spins 2.78 turns..... Twice and 4.56 turns.

If no manual hubs then you can still do the spin tire test by starting truck....engage the vacuum assisted 4wd....turn engine off...remove 4 bolts from differential end of driveshaft.....let DS drop but not to let it separate at the slip.....jack 1 tire off ground and do the test.

You could also remove the FRONT aluminum cover and count the pinion teeth. 9 teeth on the pinion and you have 456 gears because no other ratio for your year of truck has 9 teeth.