rear axle gears info?

[01vortecpwr]

just wondering if i could find out what gears are in my rear axle by the vin# or do i need #'s off the axle itself

[ToughBowtieTruck]

The VIN itself won't tell you, you have to look at the build sheet for the truck in the glovebox. It'll either be a code or the ratio. If not, you need to investigate the axles.

[01vortecpwr]

i see i know there use to be one in there went to look today..and it was gone. pretty positive it use to say 4;56. its a 1981 k20. heavy duty chassis.

[7387chevynut]

You also have to make sure those axles are ORIGINAL to the vehicle...................only real way of knowing is PULL the diff covers......and check the side of the RING GEAR..........there will be a GM stamp followed by some numbers.......like   11/41.........that is your ratio   take those and divide them........as an example.....that would be 3.727272....you round it up......and get 3.73.

There will also be a BUILD DATE........to tell you when the ring gears were made.........if the truck was built in 1981.........its possible your ring gears will have a build date of  1980.

[01vortecpwr]

cool thanks