axle ratio????

[71Seth]

Is there somwhere on my 78 burb that I can find the axle ratio? and if not can i figure it up without removing the cover? It came with a towing package, should it have a low gear? Hoping to be able to swap it in place of my 3.07 in my 71 c-10. Any help would be great.

[TX_Mudder]

Jack the rear end up and put it in neutral. Spin the tire one time and see how many turns the driveshaft makes.
3 and 3/4 turn is 3.73
a little over 4 is 4.10
3 turns is 3.08


Rather than mess with that, go ahead and remove the diff cover. You need to change the gear oil anyway. The ring gear will have a number stamped onto it, like 41 11.
divide those numbers.
Ratio is 3.73

-- Mike

[BigRed]

Go with TX_Mudder's second way to check. I did the first way and it was just confusing for some reason. Duh! Anyway, it's good to get in there a swap the fluid and check things out. At it's real easy just to read those numbers on the ring gear.

[71Seth]

Thanks for the input. The burb is not a daily driver, never gets drove. I just Trade parts for local parts for my 71. Saving engine adn trans. Did towing packages come with low gears that year? I need to loose hwy gear in my 71. What trucks do I need to keep a lock out for That would have the low gears?

[Grim Reaper]

If it's still there the build sheet is on the glove box door. If it's anything but the defualt axle ration for the year it will be listed. Default in 78 should be 3.08. Towing package on my 79 K5 4x4 was 3.73 gears.