Ring gear count for 4:56
 

Does anyone happen to know the ring gear tooth count for a 4:56 ratio rear axle for the 69 3/4 ton corporate style (Eaton?) that has the 3rd member drop out ( quick change style carrier)......??????
Thanks,
Dave

Should be 41-9

Sorry, thats 41 teeth on ring gear and 9 on pinion.

Thanks for the numbers. Makes it so much easier.
Dave

41 / by 9 is 4.555555555555555555555556 :)

For the record on this board::: The front axle on the 69 says 4.56 and when pulling out the rear 3rd member I have discovered that the ring gear is a 32 and the pinion is a 7 for a 4.57 ratio which is slightly lower gear ratio than the 4.56 making the front tires pull ahead slightly faster theoreticaly keeping them in front or the leader on slick surfaces Thus the truck stays in a straight ahead position rather than the back end coming around in front.
However I have proven beyond any doubt with my CJ5 Jeep with the same gear set ups that the rear end will pass the front end up with little more than a blip of the throttle at the wrong time!!!! Believe me it can be quite entertaining whether done intentionaly or by accident!!

Passengers love it too!!!!!!!!!!!!!!
Dave :devil:

Yeah the Eatons are weird like that. 4.11s, not 4.10s...4.57s, not 4.56s...5.14s, not 5.13s. My dana 60 will get 5.13 gears up front. My dad thought it was really weird that GM did this from the factory, but most people say that such a small difference wont even be noticed.

I've heard of this before, never checked it out, and in theory it makes sense. But if the front is geared slightly lower, it will turn the tires more slowly than the rears, not faster. Hmmmm.... :confused:

I think to have any noticable difference you'd have to have like 3.73s up front and 4.11s in the back with the same size tires. There was a truck like this in a magazine and it was strickly for mud bogging.
The reason for the slight variations between front and rears in production vehicles is probably more a function of design constraints between the different manufacturers. Really between 4.09 and 4.10 the difference is like 0.25% hardly noticable. You could have more variation between the tires than that. The only vehicle I had that the front and rears matched was a scout II with front and rear Dana44s.