Why can't American trucks have synchronized transmissions?

If you pull out synchros from transmission you cant shift it!))) LOL!

Non synchro transmissions are designed for non clutch shifting.

 

The gears are cut at angles usually as apposed to the straight cut on most crash boxes.

 

but Eaton makes synchro transmissions in France and they just add synchros. All other parts they share with US transmissions. I tried to shift this transmission like non synchro w/o clutch and I can pull out stick but I cant engage gear. We did tranny swap to international 9600 from ERF and we had a lot of pain becouse to shift synchro tranny driver had to clutch every time he shifts and he said he feels like his left leg goes stronger. We had some pain to install clutch servo.... no.. to install servo was easy, but to fit hydrolic clutch master cyninder! Crap! Innternational cab is not ready for this.. we had a week of work

 

The idea that a crash box is stronger than a synchro is nowadays a myth, we use them here in Europe even on heavy haulage up to 200 tonnes without problems. I drove one once on an iveco With a crash box I had a loan of , ok it took me a while to get used to it but I mastered it after a while, it just took a little practice , no real skill involved! But I can't see the point to crash boxes anymore , you can put a new guy into a synchro for his first time and he won't bring u back the gears in a bucket, I've been in this game with my own trucks for 16 yrs and never had I have a synchro box fail on me, truck makers here like scania won't even give you one as an option now because as the development of crash boxes has literally stopped they are now not strong enough to handle the torque that engines are putting out here ( up to 3,500 nm currently and plans for much bigger )

The thing is judging from this forum, Americans don't like change, they like what they know, that's great but you guys are being left behind, a synchro box helps fuel economy and the latest autos improve it even more ( scania are guaranteeing 11mpg @ 97,000 lbs on a 730 hp v8 and mercedes 12 mpg on the forthcoming actros) and because our autos are based on synchros they work Alot better with very fast smooth changes and with really simple designs are nowadays very trouble free,


I understand there is a slight weight penalty for a synchro and with your weight limits being so low you need every lb you can but that penalty is tiny and the pros far outweigh the cons

 

Nuff said.

 

Also if you miss your crash box too much you can shift a synhcro clutchless by matching the revs, had to do it some years back when the clutch master cylinder failed on my daf ( some piece of crap that was )

 

The point is cost.It is cheaper to manufacture and cheaper and simpler to repair.

Yes I would have to agree with this.Americans like the KISS (Keep is simple stupid) principal

I'm not sure about this as there are energy losses in spinning the synchro's

Yes , but these are not synchro boxes they are crash boxes or am I wrong.

Are you sure we are talking about the same amount of diesel here.US gallon is about 84% of what a imperial gallon is.

The ones I have opened are non synchro.

 

only scania uses syncro in their autos,volvo's I-Shift sliding clutches ,ZF sliding clutches and two countershafts
i would say a eaton with straight cut gears and twin countershafts or mack with three will eat more horsepower to spin all this gears and bearings,instead of euro gearbox with helical cut gears and just one countershafr

 

No, for instance , the only difference between my auto box and the manual is the top lid of it, attached to which is the selector unit, that's it! Everything is synchro here, yup those are euro gallons, sorry for the confusion, at 84% us gallon size this means they do 9.3 mpg in your terms, very good considiring it's running approx 25% heavier whitch would surly mean ( by my own experience) that running at only 80000 lbs would mean another mpg , so that's about 10 mpg +( at your weight and in us mpg) from a truck giving out 280 horsepower more than an average truck, that's #### impressive to anyone I would think, anyways it's not just the gearbox or engine that does this, it's the whole package, how everything works together along with aerodynamics , tyre choice , wheels on the road ie: lift axles and rear steer are a good help instead of double drive, every little percentage counts, the gearbox is just one of the factors

 

Never opened a Scania automated.Only ZF and I-Shift and the ZF auto's parts cost easily 5 times what we pay for the same parts in the ZF manual.

The other points make some sense though.