Afetrnoon folks,
Turned up for work yesterday and was given the keys to the only manual gearbox waggon in the fleet, a Scania R420 highline. I felt a little worried about this as i’ve never driven a manual gearbox since my test 
. One of the guys from the office was kind enough to go through it with me and after a quick ride round the yard everything was fine. 
This is where the problems started, firstly i was given a fully loaded decker and was heading to Scotland via the A66, Mmm i thought, gonna be using this gearbox quite a bit! Once coupled up i was off down the road, 2nd, 3rd, 4th…crunch grind, crunch grind 5th pulling away…just!
After a full 15 hour day i must have found 4th gear 5 times, what am i doing wrong? Why wouldn’t it go in?
When i got back to the yard i looked all over for 4th gear and still coudn’t find it!!
Regards Smokinbarrels 
(Automatic Gearbox for me!!! 
)
" what am i doing wrong? Why wouldn’t it go in?
When i got back to the yard i looked all over and still coudn’t find it!!
quote:
Shouldn’t this be in the ‘gay truckers post’■■?
Could maybe be a problem specific to your truck, I’ve had a couple of dodgy motors in the past and it’s been a problem with the linkage etc. From my experience (albeit very limited on Scania’s) there isn’t a common problem similar to what you have experienced so it may just be a wee fault with your truck.
Hope this helps a wee bit anyway,
Paul.
It sounds like it has the wrong gearbox fitted.
A 3 over 3 in a 420? 
Range-splitter 12-speed: for all engines in the range 230 to 420. Optimised for performance, economy and driveability.
Range-splitter 12+2-speed: the addition of two extra low-ratio crawlers for increased versatility. Available with most engines starting from 340.
Range-splitter 12+2-speed overdrive: designed for all applications where hub reduction axles are specified, or with the 620 engine.
Range-change 8+1-speed: versatile and rugged gearbox designed for easy driving with engines up to 470 and gross weights from 24 to 60 tonnes. 8 forward ratios plus a crawler.
Range-change 8-speed: designed for distribution and light construction applications. Available with all 9-litre engines (230, 270, 310). Compact, rugged and uncomplicated, with a simple H-pattern shift and slick operation.
6-speed: specially for light-duty urban distribution. No range-change, just a simple 6-speed shift, more like a car than a truck. Ideal for busy multidrop city schedules. Available with 230 and 270 engines.
G670: Six-speed gearbox for power-outputs of 230 and 270 hp.
GR875: Eight-speed range-change for power-outputs from 230 to 340 hp.
GRS895: 12-speed range-split for power-outputs from 230 to 420 hp.
GR905: Eight-speed plus one crawler for power-outputs from 230 to 470 hp.
GRS905: 12-speed plus two crawlers for power-outputs from 340 to 560 hp.
GRSO905: 12-speed overdrive plus two crawlers for 310 to 620 hp engines.
Sorry folks,
Forgot to say 05 Plate Scania R420, 3 over 3 with splitter. Not sure what that makes it 12+2? As you can probably see i’m not up to scratch with gearboxes.
Regards Smokinbarrels
On level roads the Scania’s six-cylinder lump doesn’t need to be thrashed to perform. We rarely took the needle beyond 1,500rpm in our progression through the gears, moving off from rest using 1-high and 3-low and then changing into high range and 4-high, followed by 5-low and a succession of half gears through to top. Choosing a full gear in the upper ratio costs a full 500rpm, leaving the motor too low in the rev range if the 1,500rpm ceiling is respected.
Courtesy of Road Transport.com
4th gear seems to be an issue on these 'boxes.
The one in my 124-420 6 wheeler is sweet as anything but in the unit I’m driving it’s anyone’s guess as to whether it’ll take it or not. Sometimes it’s like a hot knife through butter other times it will not go in.
2nd and 5th is a nightmare on our 420. I usually just give the throttle a stamp before changing up / down and it goes in no bother.
Wheelnut the R420 is a 3 over 3, range change and splitter so 12 speed, then you’ve got Crawler gear which has a hi and low split making the +2. 4th gear is nearly always a pain in the arse, its a bad gearbox, the older 124s suffer too but nothing like as badly for some reason. The 4 over 4 box they use in rigids is fine though.
The Scania 12 speed gearbox does not like to be rushed when changing from 3rd (hi/lo split) in low range to 4th(hi/lo split) in high range especially when the gearbox oil is cold.
If over the years this has been “banged in” by the usual driver/drivers it only gets worse, if it’s been “run-in” from new the problem is reduced i.e. not rushed.
One trick to warm the gear box oil is to flick the hi/lo range change switch several times to get some movement/heat in the box.
Also always set off in 1st gear when loaded or you will fry the clutch!:oops:
imho - I’ll get my coat
first make sure big selector switch at front of gear lever is in down position if you have a heavy load the small switch on the top left gives you half a gear so example: heavy load drop left switch engage 1st you’ll see a small green light appear on the dash pull away flick the left switch dip the clutch let up light goes out full 1st gear go up the box 2,3, pull the front switch up drop to what would be first there’s 4th go up 5’ 6’ come to a hill or overtakeing something flick the left switch down dip the clutch green light comes on you’ve dropped half a gear to over take or climb a hill you can leave the switch down and drive with the light on if you want but you’ll burn more fuel or once you’ve overtaken flick the switch up dip the clutch release light goes out then your back to full 6th.
hope that makes sense it took me a bit of time to get used to it .Far rather drive an auto but hey
Probably just a bit knackered.
I’ve driven a few cattled lorries now and it helps if you know how to double declutch into rogue gears. (I did when learning to drive in 1991 - one of the three cars I learnt in was a 1964 Austin 1100 with a crash first gear)
Afternoon folks,
Thanks for the replys, it looks like its the gearbox at fault and not my driving…honest !!!
Regards Smokinbarrels