ring&pinion

[bilchap]

Does anybody know if the ring and pinion from a 99 model exp will fit a 92 model.Its a Dana 35,4.10 ratio.Part number 46927.Any help will be great.

 

[IZwack]

No - the 91-94 Explorers are high-pinion while the 95+ are all low pinion.

 

[MrQ]

No - the 91-94 Explorers are high-pinion while the 95+ are all low pinion.

Not to hijack the thread, but whats the difference?

 

[IZwack]

Not to hijack the thread, but whats the difference?

The design of ring and pinion gears originate from the rear axle. In order to optimize contact area between the two gears, the pinion gear is offset from the centerline of the ring gear - typically moved down (that is to say, the pinion gear is below the centerline of the ring gear). Because of this, the teeth on the gears must be cut in a spiral in order to optimize the transmission of torque while at the same time minimizing noise (a balancing act).

So when axle manufacturers create front axles, most of the time they will typically just use the same ring and pinion gears used in rear axles. However, because they are now being used in the front axle, the two gears are rotating in the opposite direction and therefore, the teeth of the gears are actually meshing on the opposite side of the teeth - which means the interface between the two gears used in a front axle is not as strong and more noisy than when used for a rear axle.

So what can we do about this now that we're using gears made to rotate in the opposite direction? Well we can cut the teeth in an opposite spiral direction but this also means that the pinion must be placed above the centerline of the ring gear in order to still optimize torque transfer and minimize noise.

Now the Dana 35 comes in both a high pinion and a low pinion design. Sometimes the high pinion is referred to as a "reverse rotation". However, this is misleading and the differential doesnt actually rotate opposite to its low pinion cousin. "Reverse rotation" refers to the reverse spiral cut of the teeth on the ring and pinion.