"Automatic" transmissions

The other two are known as Automatic Manual Transmissions, or AMT for short. They are essentially a manual transmission with a computer that shifts the transmission, as well as operating the clutch instead of the driver.

The difference between the 2, I wouldn't know what criteria they were using to Differentiate them. I would assume it is proprietary, ie Volvo and Detroit which work as team with the engine, vs non-proprietary, ie Eaton, which is not manufactured by the truck maker.

 

there is an auto with a clutch or a gen 1 from eaton fuller. it's full auto when moving but have to press clutch at stop or to get it rolling. also clutch is exactly same like any other trans. second if eaton fuller gen II with no clutch pedal, pain in the ### to drive until you get used to it same like a car just brake and gas, still has a clutch just a different more expensive type. and then gen III from 2013 and up i believe with no clutch pedal but it actually has an actuator in the bottom that does the job of the clutch for you just no pedal in the cab drive it like any normal car, most of your auto nowdays in kw pete and some frl and volvo actually come with this trans all three made by eaton fuller. there is other ones out there like the volvo i shift its a dream to drive great on fuel and very strong but if something breaks down you need to mortage your house to fix it. clutch for it around 4500 and trans with electrical and everything about 20K. the other type no really popular is the zf fredom line full auto great to drive expensive and very hard to fix since there is not a lot of mechanics that know it well and parts are really expensive. also the last few years FRL came up with a DT12 trans i believe made by allison pretty nice to drive. so everything besides the GEN I is full auto with no clutch pedal at all.

 

My truck has the DD15/DT12 combo from Detroit.
Does that classify as a fourth type?
This combination is strictly from Detroit and designed to work together. And they do it very well.

Pretty sure this one is of the automated clutch type. No pedal and no intervention by the driver. It just does its thing.
Drivers that don't learn to use it correctly will probably hate it. But it is a very nice thing for the rest of us.

 

A clutch is not a requirement for "AMT" designation. The DT12 is an automated manual transmission as it doesn't at all work like the auto tranny in your car. Didn't realize anyone made a true automatic for class 8 trucks. Also, DT12 is made by "Daimler" not FL and without help from Eaton.

 

Sorry about double post.

 

Alison transmission was the first heavy duty transmission. They use them in garbage trucks and fire trucks and RV. They are like car automatic I believe. Not very good for big truck. Then they came up with the idea on having a computer that could shift gear. Eaton had transmission with ESS Electronic Synchronized Shift. It was first truck transmission that could sync the engine RPMs as you shifted gears. Easton had first autoshift transmission but they would get stuck in gears and the computer would freeze up. Eaton just added servo motors to replace the gear shifter and a computer

Then Volvo had first transmission the I-shift that was real computer controled and clutch that communicate with the engine. It was a completely new transmission design I would say. Easton just added a computer and Volvo ki da designed it with the computer as part of the transmission.

Then Detroit basically has the same design. Today they both are still truck transmission but I would say very heavy into the computer. It useless without the computer to control it but the act like car automatic transmission when it not. Like Detroit will give you a warning if you get the clutch to hot and it can sense the load or hill and change shift points. I don't think Eaton does that because they still just are adding a computer

 

The Detroit transmission will hold the brakes for you on a hill. I can do that because the transmission and engine work together and the truck. Eaton I don't believe can to anything like that because it doesn't have that kind of integration. It just a simple computer on and old style truck transmission.

 

Allison auto is a true auto transmission like a car. It has a torque converter, planetary gears and clutch packs.

 

I had to climb out of a steep driveway yesterday, loaded. Truck was rolling backwards. Push brakes and start over, pushed HSA button and try again still rolled backwards. Finally just put my left foot on brakes and right foot on go pedal and got up and out of there that way.