Shifting Q's

You're spot on except the part about AutoShift trannies having synchronizers. They don't. The engine's computer is doing the same thing that you have been doing yourself. It floats the gears exactly as you do, except that it won't miss gears nearly as often.

 

I like the concept of the auto shifts.
I just do not know if I want one, I may get lazy with it lol.
They would be nice in situations of sudden deceleration though. No time for proper shifting in some emergency stops. And the jake will work better with it downshifting quickly for you.
I do not know if they react fast enough in those situations to really help with stopping distance though. I need to read up on them more.

 

If you can be hard on the brakes in a panic situation, think to down shift quickly at the right time, and apply the jakes again, then you can do what an autoshift can.

An autoshift is an Eaton Super 10 with automated shift controls. It floats every gear. The Meritor 12 speed clutches on every shift. Cat had some ploblems with the C-13 with a Meritor behind it messing up crankshafts and thrust bearings because of clutching every shift.

 

I seen you ask this more than once in this forum.....so

I have to redirect this question...and respond with a question. And admit my lack of knowledge here.

But what the hell are you talking about ????

It's been over 20 years since I drove anything that ran down the highway, that didn't have a synchronized gear box.

Now, they may not be the type of synchronization you are referring too. I dunno. But you're not going to find a modern gearbox in the US that isn't synchronized.

 

autoshifts have a clutch pedal, ultrashifts have no pedal and use a centrifugal clutch. I'm aware they're not like an automatic tranny in a car. there is no clutching involved in the shifting of an autoshift, like kwray mentioned - the computer floats the gears.

all the old timers always say there is no way they'd ever drive an automatic truck, that they would hate it. but after they do, they gush about how great they are and can't imagine going back to a manual. also, being able to have the jake on to downshift is nice, especially with a heavy load. but in a panic brake situation, it can't downshift any faster than a human could manually downshift so it simply goes into neutral. what DOES help with stopping distance though (and preventing jack knifing) is anti lock brakes.

 

It is rare that i have a true emergency stopping situation.
Quick ones here and there, but not many emergency stops. I always allow allot of following distance, and look far enough up the road to have a good picture of what is going on.
Normally if I need to stop fast it will be brake, skip a gear downshift, brake, skip a gear downshift lol.
By the time I do all that I am almost stopped. Sometimes i have skipped several gears on the way down. But my brakes are always very good. I know I can trust them, and I really do not use them very often.
I think I may even use them more in the winter than any other time, and that is just a little light pressure now and then to keep the ice melted. Otherwise my jake is on all the time when on the road, and it slows me down just fine.

I did read some really good articles a few years ago with testers loving how the auto shift transmissions worked in mountains. They would set the cruse at there needed speed (with a loaded trailer), and they would let it do its thing. They claimed that it maintained speed very will up and down the mountains. I don't know.
Going up I may trust it. Going down I think it would scare the heck out of me the first time. Going down a mountain with cruise on lol.

Oh BTW. We got off track for this thread.
How did the shifting go.
You said you were doing better, were you able to help your classmate?

 

In this country you would be hard pressed to find any manual transmission in any truck bigger than a dump truck that has a synchronized transmission. I'm referring to super 10, straight 10, 13, 15, 18 etc. The only part of these transmissions that is synchronized is the range box. Otherwise, anything that you move yourself apart from the rangefinder/splitter button is gonna grind going into gear. The only synchronized truck transmissions you will see are 5 and 6 speed Eatons in straight trucks.

 

Yep looking for another answer possibly from another poster and i said i had asked before, and yep not the type of synchronization i was talking about. You will have to forgive my repetitiveness.

 

i hate those real loose shifters

went to put one into 7th (8 speed) and it smashed my hand between the stick and the dash pretty good

 

Transmissions in the US have been utilizing synchronizers for many years. And it's not just the range box.

While they are not a "true synchronizer" in it's purest form. They are syncromesh and they are considered synchronizers, none the less.

I did understand the posters comment about a crash box. Early crash box models, were/are a complete #####. And they still build them....

No offense meant to you. I just didn't understand what you were talking about. So I looked it up. It's commonly refered to a "Power synchronization", here in the states. And I've heard MANY good things about the Volvo.