G’day fellows, I’m a bit late to the fray, but will offer my knowledge and experience of forty years playing with the ubiquitous “bush ranger”, in Australia.
We had 9,10, 13, 15, 17 and 18 speeds here.
9 speed: Available in 6, 9, 11, 12 and 14 series torque ratings. The 11 and 14 series had finer gears and were marketed as “Multimesh” as they had more teeth meshing simultaneously. This applied to all 'boxes in these series including all 18 speeds.
They were available in RT (direct) and RTO (overdrive). Any competent mechanic could convert a direct box to overdrive, simply by swapping the 8th and 9th gear’s position on the shaft. This also changed the gate pattern to put top gear right and forward. These boxes were colloquially refered to as “round the corner overdrive”.
10 speed: Pretty much the same as the 9 speed but all positions were used twice. First gear was taller than its counterpart in the 9 speed.
13 speed: Basically a 9 speed with an overdrive range added to the back of the 'box. This enabled the splitting of the top four ratios. To the best of my knowledge, latterly the overdrive unit was factory fitted to RT 9 speeds to create an RTO 13 speed. The patern was 1-5 with the 3 position range change selector in low, compound shift to 6(2) and the selector in the direct (middle) position.7th was selected wit a simple range change to the O/D position. Rinse and repeat through to 13th gear. These knobs were a black coloured plasic, until superceded by the two switch, 18 speed style. I realize I’m no doubt trying to teach many of you blokes to ■■■■ eggs but I’ve only explained specifically, to compare it with the sequence of the older 13 direct.
*Prior to the upgrading to 11 and 14 series a RT 13 was available, these had the chrome knob. My memory is a bit hazy but IIRC, the sequence was 1-5 with the range selector in low, 6-9 in underdrive then 10-13 in direct. The selector was also on the opposite side to the RTO selector.
15 speed: Basically a 10 speed with a deep reduction range added. It actually only has 13 useable ratios. The deep reduction could be selected by use of either a second up/down air switch on the gear lever or a selector somewhere on the dash.
The correct sequence is as follows. Deep reduction engaged, range change button down, 1, 2, 3; deep reduction disengaged, 1, 2, 3, 4, 5 (4-8); button up, 1, 2, 3, 4, 5 (9-13).
17 speed As far as I know, never sanctioned by Mr. Fuller, but Aussie truckies saw the need for so many gears long before the manufacturer released the 18 speed. A backyard re-plumb enabled the bottom half of the box to be split also.
The secret gear. Ratio-wise there is no point using it in sequence. First gear position, used in anything but low range puts too much torque through the higher range, it should only be used under light loads.
I have never, in over forty years of Road Ranger use, come across one that couldn’t be changed clutchlessly. I currently drive a Western Star with a fully manual RTLO 229 18 and own a MAN coach, with a factory fitted RTO 6 10, that i am converting to a mobile home.
The secret to trouble free Road Ranger operation is clean air.
My musings are in no way definitive, just the best my old rememberer can muster.
It happened all the time to me loaded and also on hills when empty, even when pulling empty up the slope from our garage, it was fine empty on the flat though. Anyway I reported it, however nothing was done so I put up with it for a week or two but it wasn’t good and I was expecting the propshaft to drop off when it jumped out and then shot back into cog again. Still nothing happened and I had some holiday booked so had a week off.
Robert