After 27 years of trucking, from 48 states to local distribution, driving 13-speeds, 9-speeds, and 10-speeds (and Super-10, best forgotten), I now "play" with two school buses (see my Intro thread).
They have the Cummins 5.9 engine, and Allison automatics (one MT643 and one AT545).
I'm no fan of automatics, and I also expect these Allisons to fail sooner or later.
So I'm thinking of converting to a "real" transmission.
The 5.9 obviously does not put out much torque, but I want to allow for a future re-power to the 8.3 or even larger, since I intend to keep these buses another 20 to 30 years.
And I'm thinking 10-speed, since that would be easiest to teach others to drive, and I believe those are especially plentiful in salvage yards.
So.... I'm trying to learn what-is-what.
Rockwell, Spicer, Eaton, Roadranger, Meritor, Fuller... they all seemed the same to me when I was driving them. And now, when I search for transmissions online, I wonder.... Are they all the same, just by different names because of corporate name-juggling?
The model designations seem similar... RTO-something-10 and so on.
The "O" means the top gear is an overdrive ratio. And that would be good to have. The "something" is torque rating, but the system is unclear to me.
Does there exist one chart or website or whatnot that explains it all?
Finally.... Obviously, I happily drive transmissions with no "car type" synchronization. And my buddy who often shares the driving... he still owns a stock Model A Ford, so he can manage.
But I seem to have read that some truck transmissions now have "car" synchronization? That would allow us to put others at the wheel (with proper training otherwise).
Any and all guidance is appreciated!