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 Post subject: truck transmissions
PostPosted: Sat Nov 08, 2008 13:52 
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I watched Top Gear last week with the trucks and was suprised how they struggled to change gear.

I drove trucks in the US for a couple of years and with the exception of the Allison autos the the Peterbilts we had, most of them were awfull crash boxes. In tractors that I'm far more used to driving we have these lovely gearboxes (miles better than car gearboxes) where we hardly ever need to use the clutch and it's all done electronically, never mind the DynaVT that's coming my 8-) way next week that doesn't even have gears...

So what is the deal with lorry gear boxes? I know that there are nice electric semi powershift type gear boxes available, but how widely used are they? I would have thought the clutch pedal was as redundant in a truck as it has been in a tractor for years, it's not like they have that many gears.


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 Post subject: Re: truck transmissions
PostPosted: Fri Nov 14, 2008 20:25 
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Location: Diesel City
It was a good episode of TG wasn't it. I enjoyed it immensely.

Re: Transmissions.

The TG group was only allowed about £5k to purchase the wagons so naturally they got prehistoric cast-offs.
The Scania probably had the straight 4 over 4 layout. The ERF almost certainly had this too as I can't for the life of me imagine Hammond figuring out Eaton Twin Split in just that show.

The Magnum will definately had standard 4 over 4 "side-swipe" range change.
Probably only the Scania (once it built its air up) gearbox will have been smooth for the age of the vehicles. Ironically had the ERF ( Edwin Robert Foden - for those that didn't know what ERF stood for) been fitted with the Eaton Twin split it would have changed gear far easier... If they knew how to use it.

As for the flat out "EAT MY MAGNUM" speed.
ERF was always going to win that. Cummins are screamin meanies. My old (new then) 325 ERF pulling a 15"10 Taut annihilated a 420 Scania pulling an empty flat on M6 north of Carlisle. Naturally that was top end speed only, but it was funny to see him gripping the wheel as this cheeky lil 325 Bossed him.

Todays Transmissions
All our vehicles are now fitted with full auto boxs. All means Volvos, Scanias, DAFs, Mercs, MANS & Renaults. The Scanias have retained the clutch for start/stop only. The autoboxs work very well but a professional driver still needs to think ahead that the approaching hill WILL slow them down and so knock it into semi-auto and drop a cog in readiness. You would be amazed at the amount of prix/n00bs that leave it in auto though and stuff up the traffic flow behind them.

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 Post subject: Re: truck transmissions
PostPosted: Thu Mar 19, 2009 15:01 
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Joined: Sun Apr 24, 2005 12:52
Posts: 947
Location: falkirk
I HATE AUTOS :x

as outcast sais, all trucks these days are autos although the 5 series does indeed have a clutch pedal (so does the actros :D ) but i cant figure out why. tesco have a mixed fleet of manual and autos and when it comes to driver control the difference is unquestionably evident. the shop staff in coatbridge have commented before on them. any driver takes at least 3 times as long to put an auto on the bay compared to a manual driver. the DAF CF auto is absolutely useless for low speed manouvres. it is either moving or not moving whereas a manual obvious has the advantage of using the clutch to 'edge' the vehicle into position. i have also had problems pulling away uphill with a fully laden volvo FM in bolton. the auto kept trying to pull away in 4th and stalled so i had no option other than to over-ride and select first. although this is not much of a problem to do in practice, in principle does it not defeat the purpose of an auto when you are forced to select the gear yourself anyway? :?

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