Mark T

You do realize that based on that theory, tens of thousands of single countershaft transmissions have nothing "centering" mainshaft gears. Like for instance in an M Drive

Then there's another bushing like that in the auxilury after the auxilury drive.

I'm pretty sure the gears on the mainshaft are splined inside and ride the mainshaft. It's all pretty tight. Floats, yet tight. Not a clearance that can be adjusted like the limit washers for fore and aft. More like good or bad. The mainshaft shares a common centerline that also isn't adjustable. Good or bad. Bearing on the input, bushing between (input) rest of the shaft and bearing where it goes into the auxilury drive. All floats, but it's tight. Doesn't rely on countershafts to give support in any way.

Those splined gears on the main shaft are a very close fit to the splined part. Like enough for oil and that's it. Perhaps I should have used the word "bushing" as opposed to adding an (S) Point is none of the mainshaft assembly relies on countershafts for support. It's a delicate balance in there of floating and not. If anything on a mainshaft does more than float as intended ??? you have problems.

Mainshaft gears in a Fuller have the round part on the other side of the clutching teeth that ride on the shaft or just the inner teeth that are against the mainshaft (yes they float on there and are shimed into position front to back) . The input shaft ??? I'm pretty sure there's a bushing in there where it goes into the mainshaft. Which is where it makes the mainshaft assembly able to turn as per gear selection. None of the mainshaft assemble relies on countershafts to support it's centerline.

If you're centering your mainshaft with the countershafts ???? you have bigger problems than how many countershafts there are. Fullers are timed cause of the cuts for where they're keyed for the gears on the countershafts. Countershafts are either welded fast or keyed and press fit. Mainshafts "float" but are still centered by their bearings and bushings. Their centerline relies on the bearings and bushings . Other than the being loaded up by torque, they are not supposed to do much but mesh with and drive the countershaft(s) One countershaft miss'n from a Maxitorque ?? on highway, somewhat low power ?? never miss it and probably a little easier to shift.

There's a couple older threads about the two countershaft transmission. and yes, the Liberty is lust worthy

I went back and looked at that link again. That's an overdrive. Probably matched with like a 7.5 axle (or lower) that old post says they're the same as a triple countershaft . Probably the same as any direct in that series. Seems 1st wouldn't be much below 8 to one if that even.

There's an old thread hear from back in '09 about a fire truck with one and a 300 (285) nothing about ratios. If I had to guess likely not an overdrive, so the ratio set in JoJo's response seems plausible. Guy points out they're easy to shift.

Pretty hard to simulate conditions it would go through while running. Should be looked into though. I bet it's why you mentioned the part about it being loud.

That's cause you guys down under are typically engaged in extreme truck'n. Maybe it's not totally dust dust dust. But I but your trucks spend way more time at full power , which equates into way way more air moving through 🤔 everything

Yes. Separated. Living separate lives in the same house. I'm pretty sure a strata tube didn't use an actual filter element per se but the tube itself was like a cyclopac or psychopath or something that separated the debris enough to go through the tip fan and intercooler. Anyway.....that T after the Farr ? Not a good idea, unless somebody really likes changing cylinder kits.

They didn't require super clean air. Trucks with a strata tube I don't think even used a filter, just the scoop and some cyclonic (?) action in the tube. I can't for the life of me remember what the inside of one of those air cleaners with the over and under outlets looked like inside. But I do remember one filter was for the engine and one was for the tip turbine. (where's Mech ???)

Puts a whole different meaning to the term air ride. and that's pretty f@#k'n cool

Ummm no it's not. The tip fan only is spun when there's enough manifold pressure to bleed off to spin it. From the outlet of the intercooler back to the ducting from the air cleaner there's nothing filtering air that can pass in there with the tip fan not being fed. Could explain why he mentioned it seemed loud.