chappy261:
it can sound a bit complicated but probably can get the idea after a day or 2…or 3…or 4
Hi chappy261, it might seem a bit complicated, but adding a splitter to an 8-speed effectively doubles the number of gears available to you.
This is particularly useful when climbing long, steep hills.
On the flat, you can ‘skip’ some of the 16 gears like you can sometimes with an 8-speed. The number of gears you use/skip at any given occasion will be governed by your actual GVW and any gradient.
I wouldn’t expect this to come in a few days, we’re all still on a learning curve.
thanks for ur nightmare pics rog!
i learned in a merc axor with the slap-over 8-speed box and ive then driven a daf cf85 with the auto box for work, but thats only been the once for about 200miles!
I posted this before but thought it worth posting again…
I am going to try and explain a gearbox with a splitter and a range change.
The splitter is usually another switch on the gearstick that will SPLIT each individual gear into it’s own high and low mode.
When in a gear and changing that gear to either high or low, the SPLITTER switch is used and the clutched is dipped to make it happen - the gearstick does not move.
I am going to try and describe going up and down ALL the 16 gears - this might get boring
Starting in 1st with splitter switch set to low = 1st low
splitter switch up and dip clutch = 1st high
splitter switch down and put into 2nd = 2nd low
splitter swich up and dip clutch = 2nd high
splitter switch down and put into 3rd = 3rd low
splitter swich up and dip clutch = 3rd high
splitter switch down and put into 4th = 4th low
splitter swich up and dip clutch = 4th high
NOW THE FUN BIT…
spltter switch down, range change switch up (or if ‘slapbox’ - slap right) and into 5th gear = 5th low
splitter swich up and dip clutch = 5th high
splitter switch down and put into 6th = 6th low
splitter swich up and dip clutch = 6th high
splitter switch down and put into 7th = 7th low
splitter swich up and dip clutch = 7th high
splitter switch down and put into 8th = 8th low
splitter swich up and dip clutch = 8th high
And now, coming down the gears starting in 8th high
splitter switch down and dip clutch = 8th low
splitter swich up and put into 7th = 7th high
splitter switch down and dip clutch = 7th low
splitter swich up and put into 6th = 6th high
splitter switch down and dip clutch = 6th low
splitter swich up and put into 5th = 5th high
splitter switch down and dip clutch = 5th low
NOW THE FUN BIT AGAIN
splitter switch up and range change switch down (or if ‘slapbox’ - slap left) and into gear 4 = 4th high
splitter switch down and dip clutch = 4th low
splitter swich up and put into 3rd = 3rd high
splitter switch down and dip clutch = 3rd low
splitter swich up and put into 2nd = 2nd high
splitter switch down and dip clutch = 2nd low
splitter swich up and put into 1st = 1st high
splitter switch down and dip clutch = 1st low
My left arm hurts - well. not this time as I copied and pasted it
As I am waiting for my C training to start (24th march) and being unable to contain my fears over these gearboxes, even after reading this comprehensive guide to the 2 most common types, I thought it best to book a couple of assessments with the local training schools (at £20 a go for about an hour, it’s defo money well spent), as it turned out, both use completely different vehicles, and I have been lucky enough to experience both a 4 over 4 and a 4 beside 4. My first time out was in an old volvo fl7 with a 4 over 4 gearbox, and i discovered i didn’t have any trouble with it whatsoever, being that i could just “feel” the gearstick whenever i wanted to check which gear i was in, and changing the range was really quick and very easy. I had a lot more trouble with the other truck, a MAN of some kind with the 4 beside 4 arrangement and a splitter to take it up to 16 gears. I didn’t actually have any need for the splitter, but I had a nightmare changing between the ranges, and forgetting to check the light on the dashboard to see which range I was in. The other problem I couldn’t seem to overcome was that in the low range, the gearstick rests between 3rd and 4th, but in the high range, it rests between 5th and 6th. I kept dragging the gearstick through the gate into the low range when I was changing down the 'box from 7th or 8th. I have no doubt that I would get used to the 4 beside 4 over time, as I used to be a 3.5T driver, and I was changing between different vehicles on a daily basis, all with different gearboxes, but I gotta say, my preference would definitely sit with a 4 over 4 (added to the fact that I thought the MAN was just nasty and the volvo was a lot nicer and easier to drive).
If you click the link in my signature or these truck pics it will lead you to an index where you can access a lot more info which may be of use to you
BEFORE you book your training, READ THIS… - I suggest the trainee-to-be visits the training school, meets the head person(s) and has a quick look at the truck BEFORE parting with any money.
EBGBz:
… but I gotta say, my preference would definitely sit with a 4 over 4 (added to the fact that I thought the MAN was just nasty and the volvo was a lot nicer and easier to drive).
Me too
The trick with the ‘slapover’ is to ‘slap’ - leave it alone for half a sec in neutral - engange
With most gear changes in any type of vehicle I recommend “saying ‘hello’ to neutral” - out of gear - hello neutral - into gear
I think I understand the 4over4 box but the truck I will be driving when I qualify is an old Merc 6 wheeler 2628 12 speed which as you look at the top of the gear stick has six gears laid out and then a switch at the front of the lever, so is this like a half gear high and low for the six gears giving you twelve gears ! geez I hope this makes sense LOL
Mix-Master:
I think I understand the 4over4 box but the truck I will be driving when I qualify is an old Merc 6 wheeler 2628 12 speed which as you look at the top of the gear stick has six gears laid out and then a switch at the front of the lever, so is this like a half gear high and low for the six gears giving you twelve gears ! geez I hope this makes sense LOL
I know EXACTLY what you mean
It is a straight 6 gearbox that SPLITS each gear into HIGH and LOW.
With it being empty you will LIKELY start in 2 low then 4 low then 5 low (20 mph) then flick switch up and dip clutch (leave stick where it is) to activate 5 high (30 mph) - NOW FLICK DOWN switch as it give you the option to go 6 low (40 mph) or drop back to either 5, 4, or even 2 low. The high/low will not activate until the clutch is depressed
6 high is the 50+ gear.
hope I have described this ok as I’m feeling a little tired
You are welcome but just remember that a fully laden truck may require you to go through most of the gears in sequence when accelerating -
1H, 2L, 2H. 3L, 3H. 4L… ETC but for the 2L to 2H for example, only the clutch will need to be dipped - for say, 2H to 3L then the switch (FIRST) then the clutch and change of gear will need to be done.
Mix-Master:
I think I understand the 4over4 box but the truck I will be driving when I qualify is an old Merc 6 wheeler 2628 12 speed which as you look at the top of the gear stick has six gears laid out and then a switch at the front of the lever, so is this like a half gear high and low for the six gears giving you twelve gears ! geez I hope this makes sense LOL
Hi Mix-Master, That makes perfect sense mate…
I’ve used that type of gearbox, and you’re spot-on as to the use of it.
Mix-Master:
found this vid on youtube for a 12 speed
Hi Mix-Master, I have to agree with ROG and say that the gearbox in that video is a range-change plus a splitter.
The shift pattern on the top of that gearstick is arranged in the shape of a capital “H” with one of the ‘slots’ being for reverse.
Now imagine that there’s three slots left for the forward gears…
Set the range-change button in ‘low’ range, then use gears 1-3.
Whilst in 3rd gear, set the range-change switch to ‘high’ then shift the stick into the slot for 1st gear, which has now become 4th, cos you canged the ‘range,’ then carry on as you’d expect until you’re in 6th gear.
Now imagine that you have another switch that ‘splits’ each individual forward gear into ‘high’ and ‘low.’
That’s how the Volvo gearbox in the video works.
You were spot-on about the 12-speed Merc gearbox in that there are six ‘slots’ and a splitter, so you have 12 forward speeds without the need for a range-changer.
I do hope that the video you found didn’t serve to cause you confusion, cos you’d got it right at the first attempt when you described the Merc 12-speed gearbox.
When I was training I found that changing from 4th to 5th in a scania equipped with a range change always gave me a false neutral unless I took it really slow. 3rd to 5th never gave any problems regardless of how fast I changed but it was an 800000km truck…
I wouldn’t expect this to come in a few days, we’re all still on a learning curve. 
