last week i was given a short spin in a scania r420 topline with a 3 over 3 gearbox and splitter. Im used to the scania 4 over 4 in the rigids and have no problem using them but this gearbox was just a disaster to use. I had to keep double clutching going up and coming back down the box and I kept having to look back down at the gearstick to see were the gears were because it was very confusing and at the same time trying to steer the lorry through busy rush hour traffic. id say if I had another half an hour with It I would have the hang of it but im just wondering has anyone else had the same problem.
I drove a 124 470 for a mob a few years ago when I was on agency work and it had the 3 over 3 box as you describe. I found it easy to get used to but I had to keep double clutching it to make the gear changes smooth. Played more tunes than an Eaton Twin Splitter if didn’t. 
Double declutch in a synchro box?
We had some scanias with 3 over 3,
When the linkages wear and/or the gearbox wears they were as you described although they did seem to get better as things “warmed up”.
No offence, but looking at the gearstick will not make the gear selection any easier.
redboxer850:
We had some scanias with 3 over 3,When the linkages wear and/or the gearbox wears they were as you described although they did seem to get better as things “warmed up”.
No offence, but looking at the gearstick will not make the gear selection any easier.
I had to keep looking down to see where the gears were because the 3 over 3 was completely new to me and I kept getting confused but as I said another half an hour with it and I would’ve got the hang of it.
Yes the box is a pig coming back down the gears when you range shift it especially and worse when cold, double declutching does help a little.
Never drove a Scania/Volvo with what i’d call a good gearbox, synchros always baulk, not a patch on the competition.
kr79:
Double declutch in a synchro box?
it was a 2006 lorry with a lot of miles on the clock so the syncros would have been a bit worn and it was cold aswell.
Juddian:
Yes the box is a pig coming back down the gears when you range shift it especially and worse when cold, double declutching does help a little.Never drove a Scania/Volvo with what i’d call a good gearbox, synchros always baulk, not a patch on the competition.
I couldn’t disagree more. The 4 over 4 in my FM is brilliant.
After driving 4over4 I reckon everyone would have issues at first ,ZF now do a 3 over 3 …I dare say it is a pig if you don’t have the same truck ,and are jumping from motor to motor on a daily basis
Its a pretty crap box compared to a zf but far better than the auto box’s in mercs old and new.
I’ve got one at the moment, worst gearbox I’ve ever had but I’m used to various Eatons. Got used to it but if you don’t double declutch it makes you look a fool. I suppose it got that right at least its trying to be a proper gearbox. Can I have my twin splitter back now please Boss.
I find mine easy enough to use, I suppose it’s what you get used to. I drove a mates 85CF with a 4 over4 manual the other day and made a right balls of it 
I wouldn’t mind I had one for nearly five years lol
and just when you’ve got the hang of a scania 3 over 3, jump in a volvo 3 over 3 
on a H pattern, scania use 2, 3 and 4, whilst volvo use 1, 2 and 3
stevieboy308:
and just when you’ve got the hang of a scania 3 over 3, jump in a volvo 3 over 3on a H pattern, scania use 2, 3 and 4, whilst volvo use 1, 2 and 3
they don’t make it easy do they. I didn’t think Volvo had a 3 over 3 because i was in an fh one day and it was 4 over 4 and it was an absolute pleasure to drive, every gear went in first time even when cold.
jay0:
stevieboy308:
and just when you’ve got the hang of a scania 3 over 3, jump in a volvo 3 over 3on a H pattern, scania use 2, 3 and 4, whilst volvo use 1, 2 and 3
yeah they keep you on your toes
the 4 over 4 is just a range change box where the 3 over 3 is a range change and splitter box
and scania used to used (maybe still do?) the range change switch in the 4 over 4 as the splitter switch in the 3 over 3
Scania have always tried to design their own gearbox instead of using one from a proper gearbox builder. As mentioned above, Volvo also have a 3 over 3 arrangement but the Scania box is better laid out. Well worn Scania gearboxes perform better when warmed up.
Down changes can be made easier by “gassing in” rather than double - declutching, and change into low range at as slow a road speed as possible.
Just my opinions based on personal experience.
stevieboy308:
jay0:
stevieboy308:
and just when you’ve got the hang of a scania 3 over 3, jump in a volvo 3 over 3on a H pattern, scania use 2, 3 and 4, whilst volvo use 1, 2 and 3
yeah they keep you on your toes
the 4 over 4 is just a range change box where the 3 over 3 is a range change and splitter box
sorry yeah i think it was 3 over 3 now that you mention it because there was a splitter on it aswell but the gears were in the correct order like you described in your first post and that made it much easier to get the hang of.
Im already getting the impression that scania are a bit overrated and i don’t know about other trucks but i also noticed that the steering lock on the scania is very poor in comparison to the Volvo.
I find the 3 over 3 ok but the OP post makes me ask what age the truck is or more specifically what mileage / use the gearbox has had.
If its very high use then the tapers on the synchros could be worn and not getting enough grip to spin up the required gear resulting in it being hard to engage.
Another problem is when the mechanics fit the wrong gearbox oil or don’t change it when it’s due if ever.
If you are finding double declutching helps then it could be simply the extra time is all own the truck speed to come down a bi more and give a better match to the gearbox speed. When I first used the 3 over 3 I found I was trying to go too far down the box too soon, remember its 3 over 3 not 4 over 4 so the ratios between gears are greater.
iDriver:
I find the 3 over 3 ok but the OP post makes me ask what age the truck is or more specifically what mileage / use the gearbox has had.If its very high use then the tapers on the synchros could be worn and not getting enough grip to spin up the required gear resulting in it being hard to engage.
Another problem is when the mechanics fit the wrong gearbox oil or don’t change it when it’s due if ever.
If you are finding double declutching helps then it could be simply the extra time is all own the truck speed to come down a bi more and give a better match to the gearbox speed. When I first used the 3 over 3 I found I was trying to go too far down the box too soon, remember its 3 over 3 not 4 over 4 so the ratios between gears are greater.
it was a 2006 and i don’t know what mileage is on it but it has spent most of its life driving on the continent so id imagine a lot. i was told that out of a fleet of around 80 trucks that this particular one was the hardest of them all to drive because of the gearbox but surprisingly it was also one of the cleanest, it was immaculate inside and out so i assume it was always well looked after.