Further to my ramblings about earlier transmissions, reading up a bit on early Mack stuff.
Familiar with the very early 5 and 10 speed single countershaft designs, as well as the Maxitorque triple countershaft 5 speed plus reverse jobs, (including the "5+1 deep hole gear models) often coming across the Mack "compound" boxes, Duplex, Triplex and Quadruplex type. Quite often seen were a four speed Spicer auxilliary "island" box , had seen them fitted to a couple of 285 Maxidynes, albeit for really heavy haulage use, even though the particular transmission in straight 5 speed guise was better suited to the Maxidyne engine, but as I said, the two that spring to mind were both set up for float work. Express freight had a Flintstone set up with a 237 Maxidyne which had the "5+1" deep hole gearbox, used to ferry transformers around on specially built cradles. Lo-lo was that much of an underdrive that you had to come to a stop before shifting the second stick from lo to direct, you could actually walk faster and it was only to be used in either first or reverse in the main box. Saw a couple of off highway Macks in their yard in Brisbane had the same set up, but with Cummins engines.
Maynes had a few of the earlier 300,320 up to 350 Thermodynes with what seemed to be very short runs of both air change and twin stick arrangements.
Some of these had the 5 speed triple countershaft main units with the section bolted on the back which could have been either underdive or overdrive with the reverse in the rear section, which technically gave you 10 forward and five reverse ratios.
The next lot of trucks we had were the 9speed "range change" type, much the same set up as the Fuller Roadrangers except having the triple countershaft instead of the Eaton twin type.
They then added a two speed splitter section which gave you the 18 speed Mack transmission, seemed to be a lot improved over the 10 and 12 speed types.
I wouldn't even know what they are running nowadays, been away from it for too long.
Often wondered just how much torque you could shovel into those triple countershaft 5 speed (+reverse) boxes, a 375 Maxitorque used to handle them comfortably, as well as a 4oo Cummins.
The Maxi torque was available up until last year and in MP 10 600 hp with 2065 ft pou d of torque
The Maxi torque only got dropped due to low demand according to what I recall reading, such a low percentage of new trucks are ordered with a manual box (maybe in the US and Europe only) dunno about Australia
Your better to die trying than live on your knees begging