windrush:
On the Foden 12 speed 'box you could tell which drivers pre-selected the auxiliary change too early because (on dismantling the gearbox) the selector fork would be worn! Air pressure held the splitter in gear, it would often drop out of cog when the air pressure dropped. On the later eight/nine speeds (still 12 gears in there though!) the clutch needed depressing to actuate the split so fork wear was uncommon. The splitter was held in gear by a conventional ball and spring on those, though if the box was worn and jumping out of gear we would wind the air change valve open to let pressure hold it in until overhaul time.Pete.
Evening all, Windrush knows his Fodens!
Having driven, owned, imported, exported, all sorts of lorries, and so many different gearboxes, one becomes a little de-sensitived as to what was good …or bad!
I personally loved the 13 speed Fullers…Ive driven them in most European, and North American chassis, and loved their “almost without effort” ratio changes. The same could be said for the Twin Splitter…but personally I found this not such a delightful box to use overall as the 13 speed. And really, did any of us really need to improve on the abilities of the standard 9speed? How many miles extra could be covered with a 13 speed over a 9 in a “working”, (that is not the day defined by legislators), but the day that we would willingly work!!! But those "top end " splits made us feel like GP stars…amazing how 1mph gain can feel so great!
But I grew up on the Foden 12 speed,both mechanical, and air split. In its day it gave “wings” to the modest powered lorries that we drove…and status for us, who knew the mysteries of how to drive those twin stick contraptions, (even if one was a little short)! The same “mystique” was enjoyed by the drivers in France of the twin stick Bernard, and Berliet gearboxes…but it was the USAs Mr Fuller who proved that one stick could give total control, and it sat over a very reliable, and well engineered set of cogs, good for many Kilometres…and easy and cheap to repair when it finally needed work!
The same could be said for the offerings of Spicer, but you really had to work hard to make a smooth job of anything with these tough, abuse friendly, clunky opponents of driver skill! But they were ultra light in weight, against anything manufactured with an equal Torque rating!
But let us not forget the pre-cursor of the death knell of constant mesh gearboxes , that admiral twin stick, (one long, one short), but fully synchromesh Volvo 16 speed SR serie. Made even the worst driver an expert…and driven like a constant mesh, with double declutching, no one could find a false neutral…but it drove poor Ron Cater, (RIP), Ailsa`s Demo Supremo, to distraction in his efforts to educate Volvo drivers to use the synchro cones to make a single change…and no throttle “blipping”…the true enemy of fuel economy!
Much as it did with my Engineering colleagues at Saviems Blainville plant, whose insistence to my friend Pat Kennett,(RIP), when testing a Saviem GV10 speed splitter equipped outfit, to keep the throttle floored…whilst making a change…made both Pat and I cringe…and despite us showing by example how matching the revs enabled the synchromesh to work really effectively…it fell on very deaf French ears…(but of course we were both only “drivers”)!!!
But the same SM340 V8 MAN engined artic, when fitted with a 13 speed St Nazaire built Eaton Fuller box flew as a bird…despite the rather portly German Horses!!! And the effect on Saviem`s last model, the PS 30 was just the same…it liberated every single horse, and allowed them to run free…let alone the effect on M Berliets “portly” V8 356, and 360, (and for Italy…well a wee bit more)! And it made that big V 8 run as free as any bird wuth a following wind.
Then of course the premier product of the French combine…Le Centaure…in all her forms…drove through the Eaton box…and how, she sort of moved the gearlever in your hand, and the ratio swopped, the power stayed on, and the momentum was maintained…
Blooming good boxes those 13 speed Fullers…and no clutch…(or was I a cowboy)! But so was Mr Fodens, shame that those sons of Sandbach could not make a vehicle to take advantage of it!
Im away to a large Bollinger, and to think about the 13 speeds I have driven, I love them…
Cheerio for now.
