Question about 3.50 gears

[offroadfury]

How many splines are on the ring gear. I bought another 3rd member off of a guy on ebay and was wanting to try and figure out if its the ratio that he said it was before I tear mine apart. Thanks.

 

[davids78bronco]

You mean how many TEETH are on the ring gear? just count them. Count the teeth on the pinion too

 

[Seabronc]

Right, then divide the ring tooth count by the pinion tooth count and thet will give you the ratio.

 

[jgvabronco]

The correct number of ring gear teeth on the Ford 9" 3.5 ratio is 35. There are 10 teeth on the pinion. The Bronco should have 31-spline side gears and axles, but there are a lot of 28-spline diffs out there that look very similar. Obviously, the side gear teeth have to match the axle spline count you are using, but the 31-spline is what you want since it uses bigger wheel bearings and carries more load. FYI, the front Dana 44 for 78/79 Bronco 3.5 ratio has 42/12 r/p teeth, so don't get scared if you count them and they're not the same as the rear.

 

[offroadfury]

Thanks jg.