Whats the difference - Constant Mesh or Synchromesh Gearbox?

AlpineRaven · Post by **AlpineRaven** » Thu Aug 14, 2008 8:56 pm

I am thinking about applying Heavy Rigid license (been going on for years and shld have gone for it about 6 yrs ago for $500!)

The question I'm asking - what is the difference between Constant Mesh or Synchromesh Gearbox and which one is better that I should go for.... I recall one or other cannot drive specific trucks?.... I recall Dad blabbing on about crunch boxes and Synchromesh that Synchromesh drivers cannot drive crunch boxes or something I cannot remember.... Have 16 yrs in manual driving even driven & changing gears without the clutch (broken clutch cable!)

Secondly does anyone know any good training that isn't too expensive in Victoria?
Cheers
AP

Gannon · Post by **Gannon** » Thu Aug 14, 2008 9:04 pm

From what i have gathered....

Synchromesh is the same as a normal gearbox in a car.

Constant mesh is a gearbox that has no synchros (they bring the two gears to the same speed before they mesh) which means you have to 'rev match' your gears when you change them, requires 'double clutching' on downchanges

brumbyrunner · Post by **brumbyrunner** » Thu Aug 14, 2008 9:33 pm

What he said.
If you were talking cars instead of trucks you'd be calling "constant mesh" a dogbox.

Post by **Captain Obvious** » Fri Aug 15, 2008 5:57 am

what they said but i dont know about one not being able to drive the other, pretty sure you go off license grading like MH HR HC and the like, the gear box thing is just experience, im guessing better to learn on a constant mesh box then you will be able to drive anything??

my 2 c
bryan

Wilbur · Post by **Wilbur** » Fri Aug 15, 2008 9:41 am

What your refering to is the engagement when your selecting the gear. There is a 'crash' or dog box, and a syncro box. If you get syncro HR up here you can't drive a crash box equiped truck, which is pretty useless. You want to learn/get the license for the crash box type for it to be of actual use in my opinion.

YouTube · Post by **El_Freddo** » Fri Aug 15, 2008 10:18 am

AP - I've heard good things bout Decka training in Shep or Altona from memory. I'll find out from my mate where he got his done.

Got the "dog" box

I double the clutch on normal driving anyway, its just matching the revs on the way up that needs to be done - basically you don't use the clutch...

Cheers

Bennie

tex · Post by **tex** » Sat Aug 16, 2008 12:40 pm

I got my HC through a private bloke in shep (not decca) worked out a lot cheaper but decca do week long courses that will take you through the lot. The crash box takes a fair bit of getting used to but as mentioned its pointless not getting. As for the licence I don't think there is any formal qualification in either ACT or VIC but I know for a fact it has merritt in NSW. But double clutching was last covered a long time ago on this site.

chubby37 · Post by **chubby37** » Sat Aug 16, 2008 1:28 pm

you really need a licence for a dogbox?wow i thought it just went off class not what box was in the truck..i only have a MR so i never got into the bigger stuff but i,m surprised they are worried about how gears are changed over being able to drive the truck....not a dig at anyone just surprised

D3V1L · Post by **D3V1L** » Sat Aug 16, 2008 1:40 pm

in wa its the same. i got HC articulated, and it took me several stages to get my licence, basically had to get syncro, constant, then constant/splitter(range), and i had to get the seperate licence for each box, which is good i guess, so u can prove urself on each box before moving up.

i did my final test in a road train with a 13speed split(range) crash box, hardest thing ive ever had to drive...lol, but knowing now how much they vary, u have to give some truck drivers credit for being on top of the ball

caus sometimes i still screw up my gearx

Busdriver · Post by **Busdriver** » Sat Aug 16, 2008 6:24 pm

When I got my Vic HR it was through work and they put us on a week long course at a place called National Skills Industrial Training Centre, I think this is like a branch of the Wodonga TAFE.
We did all our driving in a Kenworth with no syncros and a splitter,and no one said that we could not drive a truck with syncros, so not real sure about that. All up cost was about $800 about 2 years ago.

tex · Post by **tex** » Sun Aug 17, 2008 4:22 am

chubby37 wrote:you really need a licence for a dogbox?wow i thought it just went off class not what box was in the truck..i only have a MR so i never got into the bigger stuff but i,m surprised they are worried about how gears are changed over being able to drive the truck....not a dig at anyone just surprised

Yeah but the catch is if you can't change gear you can't drive, But the theory is if you coast (angel gear) down the hills riding the brakes you run out of air pretty quick plus the brakes overheat and lose all braking power...
On another note catching a bus across canada and the bus driver had to drive a standard (manual) as their called here for the first time on one of the steepest windiest highways I've ever seen (between lake louise and vancouver) So I had to help give him a crash course on double clutching but more importantly matching road and engine speed aswell as the little rev between down shifts! I suppose we were lucky to escape with our heads still attatched!