Speaking of double clutching

I don't know how popular they were but I drove a 96-97 volvo with a syncro 13 spd for a while. Air assist clutch and one really screwy gear pattern but it worked ok once you got the hang of the gear pattern. Basically 1-2-3 with a splitter and a high/low range and a low gear for starting. The thing I didnt like is you shifted it like a 5 and 2 combo. low gear, then 1st low spilt/1st high split, 2nd low split/2nd high split, 3rd low split/ 3rd high split, go to high range and back to 1st gear low split and start over. Took a while to get used to it after a roadranger 10 lol, and to think I was all excited when he told me I was getting a 13 speed truck.

 

Why don't we just leave things the way they are? I can slap my ten speed around just fine.

 

most european trucks are synchronized. Apparently someone figured it out.

Synchs wear out though.

 

That's not floating...

 

Yeah, you're european. I'm talking about the US. Most guys out here float the gears and some of them would not change the way they shift for a syncronized trans. Floating is a good way to wear out the syncronizers. As for blowing up a motor, I knew a guy that did that in a 6-speed syncronized strait truck. He dropped a gear without slowing down for it and blew the motor. I ain't saying many people would do that, but that would be a new way to do it. An unsyncronized gearbox would not have gone into a lower gear. If anything, a syncronized trans is easier to shift. It requires no skill or thought and any idiot could do it. We've already got our fair share of idiots. We don't need to dumb it down any further and make it easier for them to get out here. The autoshift is already doing a fine job of that.

 

Explain exactly why double clutching is even nessesary; Can't single clutching do it?

 

Well, it depends on how you single clutch it. If you keep the clutch in the whole time during the shift, it won't go into gear, because its not synchronized. See, a synchronized transmission (and this is a really simple way of putting it) basically has clutches on each gear that bring those gears to the same speed while you're putting them together. A truck doesn't have that, and a motorcycle doesnt either for that matter.

When you upshift, you have to put the transmission into neutral for a second or two to let the engine speed drop. When you downshift, you have to put it in neutral and rev the engine up.

There's kind of a trick to floating without just plain tearing it up, which is why we're taught to double clutch it. If i let off the fuel and try to pop it out of gear, it won't just come out of gear. It has to be done simultaneously, which is hard when you can barely revmatch at all....Every once in a while i'll screw up and I'll have to tap the clutch just a little to make it come out of gear.

Anyway you can single clutch it by clutching it when you're going out of gear and not when you're going in, or the other way around, but you cant do it like a car.

Bikes are easier because the gears don't weigh anything near what the gears in a truck weigh. Plus its darn hard to grind gears on a sequential transmission!!

You don't have to revmatch at all. Just jam it in. If you slam it hard enough it'll go into gear and revmatch itself.


You know, im still trying to understand why a lot of people think a semi transmission is "fully synchronized". How on earth does that make sense to them?"

 

I think synchronized gears in trucks are a bit like the Metric system, the US isn't interested. Can't see the problem myself but i guess if the drivers don't want it. Hows your 13.5 M trailer holding up