Axle Ratio? More info

[Ogier]

Greetings all,

Ok, I have jacked up the rearend of the truck and did the whole tire turn/ count the pinion turns thing and here is what I get:

Tire: 4 full turns
Pinion: 8.25 turns estimated.

I am coming up with a ratio of about 4.84.

The closest ratio that I can see referenced is a 4.88 for the Eaton.

Given the estimation of the pinion turns, I see this as plausible.

Did I do the math right?

Thanks

[Americanrider]

I flunked that new math too... best to pull the rear cover, summer time is best to pour in some fresh 80-90 after the jug sits in the sun for a while. You also might be surprised at the gunk you will find in the bottom valley of the housing, stuff so thick it would take a week to drain. I swabbed mine out with clean rags before re-sealing/re-filling it.

[hannamet]

Ogier, like AmericanRider says, best to take the cover off the diff unless you have a tag to look at. The gear ratio is the number of teeth on the ring divided by the number of teeth on the pinion. If your driveline is turning roughly twice as often as your axle shaft, that doesn't sound quite right to me. A 4.88 ration means the rings gear has 4.88 times more teeth than the pinion. (Ring teeth = pinion teeth x 4.88). Probably be a good time to clean it out anyway. Best of luck, Brad