robert1952:
The manufacturers have to cover their backs by giving simple instructions to first-time users. They played it safe by advising clutch use. After all, many first-time users may have come from years of driving with sychro boxes, even back then (there are drivers around who started on Scanias / Volvos in the late '60s and retired never having touched a Fuller gear-stick!). That’s my guess. I suppose it’s even possible that Dr Fuller-Frankenstein devised a monster that was far more brilliant than they’d supposed, only to find that wily British drivers took no time at all to invent two different methods of ‘bunny-hoppy’, clutchless gear-changing, mysterious (but true) ‘extra’ gears, and even a notch on some Twin-splitters that enabled them to override the limiter without it showing up on the chart - I kid you not! The Twin-splitter is an immensely clever and complex 'box with enormous scope for imaginative driving. I’m a pretty competent TS user but I know there are drivers on here who could probably teach me a further set of tricks I’d never thought of (Gaza for instance!). Robert
I don’t think they mean the idea,of ‘removing’ the torque loadings on the transmission,by declutching it during shift operations,or correct use of the clutch/trans brake,is meant in the sense of ‘choice’ depending on personal view of how good/advanced a driver anyone would like to think they are.Nor is it meant in the sense of many shades of grey.‘Competent’ in this case meaning a decent understanding of the factory operations manual and more importantly ‘why’ it says what it says and the fact that what it says isn’t meant in the sense of it being ‘negotiable’.
Just to prove how ‘creative’ you could be with the Twin-splitter, let me elaborate on the two forms of ‘bunny-hopping’ technique.
Because there were different ways you could approach it, there was scope for creative individuality. For instance, I never used the clutch going up the box but always double de-clutched the stick changes coming down. Drivers less familiar with the TS used to become frustrated with down-changes when entering roundabouts etc, but there were techniques for that.
If you were down-splitting while ascending a hill, you simply selected, lifted your foot a fraction off the throttle to break the torque and the gear went through - no need to double-declutch or blip the throttle. However, when approaching a roundabout (or any other hazard), the torque was already broken, but by selecting the lower split, moving the stick into neutral, double-declutching and returning the stick to its original position, a perfect change could be executed. Done habitually, this technique was relatively effortless, ensured cleaner and more reliable changes and was particularly satisfying to use when ascending steep hills or entering roundabouts.
That was one form of ‘bunny-hopping’. The other form was for smooth upshifts, when pulling away heavy, or climbing steep hills. Say you were heavy and starting on a hill. You’d engage 1st and pull away, then select 2nd (split), and move the stick smartly into neutral and back into its original position without the clutch. This would obviate the otherwise inevitable lurch if you tried this using the clutch. Then you’d continue similarly: select 3rd (another split) and move the stick in and out of neutral without touching the clutch. Fourth would be a stick change so you’d select the 1st position on the stick and change into the 2nd stick place on the H shape, either double-declutching or clutchless according to taste. You were now out of the wood and could continue up the ‘box using your favoured technique.
Carryfast:
I don’t think they mean the idea,of ‘removing’ the torque loadings on the transmission,by declutching it during shift operations,or correct use of the clutch/trans brake,is meant in the sense of ‘choice’ depending on personal view of how good/advanced a driver anyone would like to think they are.Nor is it meant in the sense of many shades of grey.‘Competent’ in this case meaning a decent understanding of the factory operations manual and more importantly ‘why’ it says what it says and the fact that what it says isn’t meant in the sense of it being ‘negotiable’.
But the instructions for the Twin-splitter make it quite clear that the inertia brake is to be used for quick upshifts, so how am I not following what it says in the instructions? Robert
I’ve just looked back at page 1 and realised I’ve already said at the start of this thread pretty-well everything I’ve said on this page. We’re going round in circles. Robert
Carryfast:
I don’t think they mean the idea,of ‘removing’ the torque loadings on the transmission,by declutching it during shift operations,or correct use of the clutch/trans brake,is meant in the sense of ‘choice’ depending on personal view of how good/advanced a driver anyone would like to think they are.Nor is it meant in the sense of many shades of grey.‘Competent’ in this case meaning a decent understanding of the factory operations manual and more importantly ‘why’ it says what it says and the fact that what it says isn’t meant in the sense of it being ‘negotiable’.
But the instructions for the Twin-splitter make it quite clear that the inertia brake is to be used for quick upshifts, so how am I not following what it says in the instructions? Robert
Apologies if there is a difference in the instructions between Roadranger v TS. I was only guessing that the reasons not to use the clutch/transmission brake for up shifts in the case of the former would also logically apply in the case of the latter.With no logical reason as to why it’s wrong in the case of the former but right for the latter.
IE as I said at best the use of such braking for up shifts is effectively similar to just turning a constant mesh box into a form of synchro one by just using the trans braking to act as the synchro.In either case to compensate for incorrect matching of engine and road speed.The results,as usual,then being as described by Pat Kennet previously,in just transferring the problem further along the driveline to the clutch/flywheel interface in the form of engine and input shaft mismatch.Thereby either heat stressing the clutch and/or imposing an incorrect torque loading through the transmission when the clutch is re engagedThat’s even without the possibility that such brakes aren’t actually designed to be used for that purpose in the case of upshifts.
Although having said that maybe the inconsistency is just another to add to the idea of instructing de clutching between splits without also providing clutch actuation for splits.
Carryfast:
Apologies if there is a difference in the instructions between Roadranger v TS. I was only guessing that the reasons not to use the clutch/transmission brake for up shifts in the case of the former would also logically apply in the case of the latter.With no logical reason as to why it’s wrong in the case of the former but right for the latter.
I think that the logical reason is simply down to this: the old instructions didn’t discourage use of the clutch-brake, only modern ones obtainable direct online from the US do that. The Twin-splitter , which basically only ever took off in Britain, had instructions that actively encouraged it. The US has all sorts of quirky rules like insisting on sequential gear changing instead of block-changing so perhaps it has something to do with their rules; or far more likely it is to do with US litigation culture. I’m quite sure those instructions were written only for US drivers and for less than mechanical/scientific reasons. That’s the only logic I can see in it! Robert
with regard to manufacturers instructions , i had been driving erf fitted twin splitters for a few years when i changed jobs to a man operator . they had a new man with the twin splitter and the driver wasn’t doing very well on it .the upshot was that the man agent sent a demo driver out , bloke who knew his job , and he taught the driver how to handle it properly . the amusing part was that what he taught him was what i had been trying to instill into him for the past month . he couldn’t listen to another driver , but the demo driver was a " professional " . he also taught all the tricks like bunny hopping etc . dave
rigsby:
with regard to manufacturers instructions , i had been driving erf fitted twin splitters for a few years when i changed jobs to a man operator . they had a new man with the twin splitter and the driver wasn’t doing very well on it .the upshot was that the man agent sent a demo driver out , bloke who knew his job , and he taught the driver how to handle it properly . the amusing part was that what he taught him was what i had been trying to instill into him for the past month . he couldn’t listen to another driver , but the demo driver was a " professional " . he also taught all the tricks like bunny hopping etc . dave
I’m glad that the officials recognised ‘bunny hopping’! The only alternative was to coast into the roundabout in ‘Aberdeen overdrive’ and stop at the line, clear or not, and start again: not clever in the rain with 22-tonnes of laminated chipboard on the trailer! . To be honest, I think one has to actually drive a unit with a TS in it, to really understand how they behave. Robert
robert1952:
I think that the logical reason is simply down to this: the old instructions didn’t discourage use of the clutch-brake, only modern ones obtainable direct online from the US do that. The Twin-splitter , which basically only ever took off in Britain, had instructions that actively encouraged it. The US has all sorts of quirky rules like insisting on sequential gear changing instead of block-changing so perhaps it has something to do with their rules; or far more likely it is to do with US litigation culture. I’m quite sure those instructions were written only for US drivers and for less than mechanical/scientific reasons. That’s the only logic I can see in it! Robert
Blimey in which case those old school drivers who told me how to drive the things over 30 years ago were telling me to do it the American by the book way which is obviously still out there to this day. On that note I’ll go with clutch/transmission brakes aren’t meant for upshifts,sequential shifts are better by miles than block changes,double de clutch shifts don’t float gears,and last but not least why did Fuller go for that stupid idea of torque sensing splitter actuation when you’re supposed to de clutch it between splits anyway and ‘pre selection’ is supposed to mean what it says.Ironically most of which helped me take to the ZF 12 speed just great.
The different methods Carryfast and others are quoting on clutch brake operation could be in part to do with the different types of clutch brakes fitted to TS & 13/18 speeds.
Most will be familiar with fullers 9/13/18 clutch brake on the input shaft. With only 2 small lugs locking it to the shaft, you wouldn’t want to be putting a lot of stress through those lugs. Situations such as drivers fully depressing the clutch pedal, still in gear coming to a standstill, is basically like using the clutch brake to bring the vehicle to a standstill. So I would never use the clutch brake for anything other than to slow the box to engage a starting gear.
The TS clutch brake is a totally different set up being of a multiplate air operated brake submerged in the oil inside the gearbox. (similar to a motorcycle clutch)
Memory isn’t that good, but iirc as you hit the button by fully depressing the clutch a pulse of air actuates the clutch brake for .45 of a second. That is why if the truck is rolling very slowly and you hit the clutch brake the vehicle appears to try and stop and then roll again as the pulse of air is so brief.
I never used the TS clutch brake for upshifts, only to get my starting gear. For fast changes, just pull the stick out and back in for super smooth 100% reliable gear changes.
On the subject of pre selecting gears, when driving 13/18 spd fullers I would only pre select a fraction of a second before making the change. This reduces wear on the selector fork. I have heard of these breaking due to wear which may explain why Carryfasts manual suggests use of the clutch. As soon as you pre select your pushing the fork quite hard against the gear.
Its still good practice to pre select at the last minute with a TS as the same principle applies. Anything that reduces wear and tear has got to be better driving.
colinwallace1:
The different methods Carryfast and others are quoting on clutch brake operation could be in part to do with the different types of clutch brakes fitted to TS & 13/18 speeds.
Most will be familiar with fullers 9/13/18 clutch brake on the input shaft. With only 2 small lugs locking it to the shaft, you wouldn’t want to be putting a lot of stress through those lugs. Situations such as drivers fully depressing the clutch pedal, still in gear coming to a standstill, is basically like using the clutch brake to bring the vehicle to a standstill. So I would never use the clutch brake for anything other than to slow the box to engage a starting gear.
The TS clutch brake is a totally different set up being of a multiplate air operated brake submerged in the oil inside the gearbox. (similar to a motorcycle clutch)
Memory isn’t that good, but iirc as you hit the button by fully depressing the clutch a pulse of air actuates the clutch brake for .45 of a second. That is why if the truck is rolling very slowly and you hit the clutch brake the vehicle appears to try and stop and then roll again as the pulse of air is so brief.
I never used the TS clutch brake for upshifts, only to get my starting gear. For fast changes, just pull the stick out and back in for super smooth 100% reliable gear changes.
On the subject of pre selecting gears, when driving 13/18 spd fullers I would only pre select a fraction of a second before making the change. This reduces wear on the selector fork. I have heard of these breaking due to wear which may explain why Carryfasts manual suggests use of the clutch. As soon as you pre select your pushing the fork quite hard against the gear.
Its still good practice to pre select at the last minute with a TS as the same principle applies. Anything that reduces wear and tear has got to be better driving.
colinwallace1:
The different methods Carryfast and others are quoting on clutch brake operation could be in part to do with the different types of clutch brakes fitted to TS & 13/18 speeds.
Most will be familiar with fullers 9/13/18 clutch brake on the input shaft. With only 2 small lugs locking it to the shaft, you wouldn’t want to be putting a lot of stress through those lugs. Situations such as drivers fully depressing the clutch pedal, still in gear coming to a standstill, is basically like using the clutch brake to bring the vehicle to a standstill. So I would never use the clutch brake for anything other than to slow the box to engage a starting gear.
The TS clutch brake is a totally different set up being of a multiplate air operated brake submerged in the oil inside the gearbox. (similar to a motorcycle clutch)
Memory isn’t that good, but iirc as you hit the button by fully depressing the clutch a pulse of air actuates the clutch brake for .45 of a second. That is why if the truck is rolling very slowly and you hit the clutch brake the vehicle appears to try and stop and then roll again as the pulse of air is so brief.
I never used the TS clutch brake for upshifts, only to get my starting gear. For fast changes, just pull the stick out and back in for super smooth 100% reliable gear changes.
On the subject of pre selecting gears, when driving 13/18 spd fullers I would only pre select a fraction of a second before making the change. This reduces wear on the selector fork. I have heard of these breaking due to wear which may explain why Carryfasts manual suggests use of the clutch. As soon as you pre select your pushing the fork quite hard against the gear.
Its still good practice to pre select at the last minute with a TS as the same principle applies. Anything that reduces wear and tear has got to be better driving.
The clutch/transmission brake question regards TS v the rest might be a possibility as referred to by Robert.But against that is the fact that would mean a ‘third’ type of brake as opposed to the two different types referred to in the manual.IE we’ve got a countershaft/transmission brake ‘and’ clutch brake already accounted in the case of the 18 speed at least ‘both’ with the clear instructions not to be used for upshifts.
As for the splitter issues described there that just seems to confirm the flaw contained in the idea of not using clutch ‘actuation’ of the split.As opposed to the torque/accelerator sensing actuation.The latter of which obviously creating problems regards pre selection to the point of effectively realistically removing the facility of ‘pre selection’ of splits in any real sense of the word.On that note,as I’ve said,I’m ( very ) surprised that Fuller don’t at least offer the option of clutch actuation of the splitter.
The older Foden 12 speed box was the same in that, if you preselected the split too early, it wore the selector fork away. The later 8/9/12speed box (they were all in there somewhere!) used a air valve operated by the clutch pedal to make the change and had a ball and spring to retain the range change fork in the selected range whereas the previous box relied on air. It is correct about the Fuller clutch stop fitted on the primary shaft of the 9 and 13 speed boxes, those two lugs soon broke off if abused and it was then useless and just rattled around wearing the shaft away!
robert1952:
Like the E-series, the ERF EC-series also had Twin-splitters as standard equipment; but it was the last ERF model to do so. Robert
10
I drove an EC11 with a Twin Splitter for a week or two, it was a hire motor I had to replace a Stralis that a driver had mangled and was in the body shop being put back together, the driver and I had parted company as he was a one man demolition derby and I had to drive the ERF myself.
I wasn’t a big fan of it, I had driven various other lorries with a TS and I could do all the tricks, but I didn’t like the short stick and short throw in the ERF, it felt very wooden to me. The last ERF I drove before that was a C series with an L10 ■■■■■■■ and in contrast that had a lovely gearshift.
robert1952:
You could get a decent Ford Cargo with a Ford 'box, a Fuller RR 'box or even an Eaton Twin-splitter. Here are some examples. Robert
210
At Solstor we had three 3828 Cargos on UK shunting, they had the L10-290 and a Twin Splitter, not a bad lorry to be fair, I once took one up to York when I was waiting for my motor to get back in from a trip after I had a week off, I had my boy with me too, so we had to share the single bunk, which would be a tight squeeze now as I’m about 3stone heavier than I was back then and he’s grown a fair bit in the last 25yrs too!
robert1952:
This Eurostar had a 520 V8 and Twin-splitter- fantastic! Talking to drivers of these (when I had a 420, this happened from time to time!), I discovered that 520s were usually fitted with SAMT, which was an automated version of the Twin-splitter, to stop drivers mis-using the massive torque available and straining (not breaking, you notice!) the Twin-splitter. Most people agree that SAMT was crap and had their vehicles converted to manual Twin-splitter. Robert
4
As I loved Eurostars with Twin-splitters, I’d like to treat you all to a further, small selection of goodies… Robert[emoji38]
3210
I converted my 440E52 from SAMT to a Twin Splitter, it was an absolute animal if a thing.
robert1952:
Earlier I gave examples of Seddon-Atkinson Strato mark 1s; here are some Strato mark 2s (and Stratocruisers), which also had Twin-splitter 'boxes as standard. Robert
3210
I know, I’ve done it again!
These Stratos were the providers of the all important gear linkage necessary to convert a SAMT EuroStar to a Twin Splitter, if you used a standard linkage the shift was upside down.
robert1952:
I think that the logical reason is simply down to this: the old instructions didn’t discourage use of the clutch-brake, only modern ones obtainable direct online from the US do that. The Twin-splitter , which basically only ever took off in Britain, had instructions that actively encouraged it. The US has all sorts of quirky rules like insisting on sequential gear changing instead of block-changing so perhaps it has something to do with their rules; or far more likely it is to do with US litigation culture. I’m quite sure those instructions were written only for US drivers and for less than mechanical/scientific reasons. That’s the only logic I can see in it! Robert
Blimey in which case those old school drivers who told me how to drive the things over 30 years ago were telling me to do it the American by the book way which is obviously still out there to this day. On that note I’ll go with clutch/transmission brakes aren’t meant for upshifts,sequential shifts are better by miles than block changes,double de clutch shifts don’t float gears,and last but not least why did Fuller go for that stupid idea of torque sensing splitter actuation when you’re supposed to de clutch it between splits anyway and ‘pre selection’ is supposed to mean what it says.Ironically most of which helped me take to the ZF 12 speed just great.
Throw the book away & just learn how your hearing,engine, throttle & box interact to get the best from the set up…
I was only guessing that the reasons not to use the clutch/transmission brake for up shifts in the case of the former would also logically apply in the case of the latter.With no logical reason as to why it’s wrong in the case of the former but right for the latter.
. To be honest, I think one has to actually drive a unit with a TS in it, to really understand how they behave. Robert
On that note I’ll go with clutch/transmission brakes aren’t meant for upshifts,sequential shifts are better by miles than block changes,double de clutch shifts don’t float gears,and last but not least why did Fuller go for that stupid idea of torque sensing splitter actuation when you’re supposed to de clutch it between splits anyway and ‘pre selection’ is supposed to mean what it says.Ironically most of which helped me take to the ZF 12 speed just great. 
