Differential FAQ’s

Q. Is it better to simply upgrade my diff. or should I just bite the bullet & go with a new heavy duty diff?

A. It really depends on what diff you already have, but a good rule of thumb is to not put more than $1000.00 into a light duty diff. In most cases its only a matter of time before youre either wanting more horsepower or bigger tires, which are the two biggest causes of differential failure(in the performance & off road arena anyway). For example, if you spend $1200 on a Super 35 kit( 30 spline Detroit Locker w/ Alloy axles) and a new set of gears for your Dana 35, you really havent changed the fact that youre running tiny pinion bearings, a 7.5 in. ring gear, & 2.5 in. x .188 in. welded tubing(extremely weak!!) on you rear diff. Youll find yourself frustrated when youre on the trail & you hear your $1200 upgrade blow into bits.

Q. Is a reverse rotation or high pinion really weaker than a standard rotation?

A. It all depends on whether or not you are driving a rig that has zero lift or a rig that has been lifted. If youve got any lift whatsoever, a reverse rotation is definitely stronger than a standard rotation, especially in the rear diff. Heres why: A reverse rotation set of gears drives on the coast side of the ring gear teeth when going forward, which is weaker than driving on the drive side of the teeth, but you need to take all the factors into consideration. The reverse rotation diff. housing has the pinion above the center line of the diff., which gives your driveshaft a good 4 in. lift. By doing that you take away the majority of the stress that would have been applied to the ring & pinion gears as well as the U-joints in the driveshaft. At first glance, it looks like you might lose a little strength on your ring & pinion gears, but in actuality youre gaining strength on your ring & pinion gears while also fixing you driveshaft angle. Look at it this way, a small Dana 30 front axle U-joint in a rig thats wheelin in a straight line is going to be stronger than a bigger Dana 44 front axle U-joint thats in a rig thats wheelin with its wheels cut all the way to the left or right. Its all about the ANGLE.