How do you check gear ratios?

[onebigmj]

I was looking at a thread a while ago and some guys mentioned that 4cly trucks with a 4speed auto usually have 4.56 gears. I had a dana 35 from one so I pulled the diff cover to check. The only numbers I found that ment something to me are 41-9. Does this mean anything?

Thanks

[HOrnbrod]

I was looking at a thread a while ago and some guys mentioned that 4cly trucks with a 4speed auto usually have 4.56 gears. I had a dana 35 from one so I pulled the diff cover to check. The only numbers I found that ment something to me are 41-9. Does this mean anything? Thanks

 

41-9 = 41/9 = 4.56 ratio (41 teeth on the ring gear, 9 on the pinion)

[onebigmj]

Cool. Thanks alot. It may be a 35 but a the gearing is good. Probly make a good rear for my 4banger truck. All I have to do now is regear my front axle.

[luke87]

so what would a 4 cyclinder with a 4 speed standard have?

[MJ'87]

usually 3:55

[CrankShaftKid]

jack the rear end up and count the turns of the driveshaft in one rotation of the rear wheel

[Geonovast]

There's usually a tag on the diff cover that will tell you.

 

All options(I believe, correct me if I'm wrong), are

 

3.07

3.55

3.73

4.10

4.56