- 805
- 1,451
- 93
- Location
- Mesa Colorado
Yeah, it was obvious to me on the first 500yd drive slow up hill in snow that the previous low gearing was of no value in that situation. I always wondered why this truck was so slippery in loose or wet conditions. The 3.07s + ECO still seemed "low" in 1 but more controllable as the low end CAT torque combined with the TC performed the job without producing slippage (yes!!), and no weight in the back, and no locker! Before the ecos I had the truck out in the back snow and you couldn't touch the throttle without spinning the tires, in 1.Yes the axle is splined to the outer gear, the outer gear rolls the spider gears that roll on the inner gear that is fixed to the hollow spindle.
take a pencil and lay it on the table. Place your fingertips on the pencil and roll it across the table with your fingers and palm of your hand. Note how the tips of your fingers move twice as far across the table as the pencil does. Your hand is the outer gear, the pencil are the planetaries, who's spindle is attched to the wheel hub and the table is the fixed inner gear attached to the hollow spindle. In order to get the planetary(pencil) to move at the same speed as the axle(hand/outer gear), you must first couple them to your hand, and un-couple them from the table…
again, not easy, to do so in the space allowed and in a way that will withstand the forces involved. Also pointless IMO. Traction will be your problem with or without 2:1 hub reduction, not force applied to the wheels…
I think the fascination with ultra low gearing for "rock crawling" comes from too many Moab stories, all of gas powered 4x4s with no low end to speak of. Good combo for gas, not for 860ft-lbs. And trying to make a vehicle to be ultra off and on road + highway has never been perfected except in the Abrams lol or maybe the HEMMT.
The 7.8 overall reduction seems totally unnecessary now that I've run the ecos, unless you need that milspec of what was it,, 25klbs over an 18" vertical curb? As someone who was at Los Alamos for 2 decades, thats something that is arbitrarily ridiculous and sounds exactly like what a government bureaucrat would come up with in some project meeting. I've listened to many of those "leadership material" boneheads say things that violate the most basic laws of physics and then turn them into presentation bullet points.