I am getting ready to have the d35 I got out of a 93 explorer rebuilt for my 88 B2 and I am curious which diff to run? I will be using it as an expedition/forestry road, all purpous rig and I want better than open diff traction w/o a selectable (super expensive) diff. Is a true trac w the helical gears reversed the best option, or would a L/S be better in ice and low level mud? Thanks for all experienced input.
TruTrac is a L/S, and will be the cheaper option, but needs work to operate in the front. See this link:
http://www.discoweb.org/truetracgears/index.htm (mind you it's for Land Rollover's)
Low level mud? It'll definately be better than stock. Ice is another animal, allow me to explain "Bias Ratio". Bias Ratio is the amount of torque the differential can send to the wheel that has traction, it is a factor of the wheel that has LESS traction. Say you have a bias ratio of 3.5:1 (fairly common), the differential will send 3.5X the amount of torque that the slipping wheel is
applying to the ground to the other wheel. It HAS to have the resistance of the slipping wheel. Now say you're on super slick ice, where there is VERY little traction under one of your tires, the differential will actually send very little extra power to the wheel that does have traction. Why? A very small amount x 3.5 is still a very small amount. And if you have a wheel off the ground, it won't send any power (0x3.5=0).
The next step up in $$$ is a Eaton E-Locker. Some have criticisms of it's reliability (mostly just in the 8.8 application), honestly I think its fine if you don't beat it to within an inch of it's life (as I'm sure some do).
Bottom line when I put in my ARB is this: I could fool around with an L/S diff and maybe get out, but with a locker, I have all the traction my tires are going to give me to try and get unstuck, period.