New 2018 freightliner automatic?

I would assume it will have the Detroit DT12 transmission. Remember not to use the engine brake in slippery condition. Because the DT12 transmission will downshift automatically. It different because the transmission and engine worth together to give you maximum engine brake. It will drop a gear bring RPMs up to 2,200 because that when you get maximum engine brake. So you don't want that in snow covered roads.

It you run the cruise control it also has automatic engine brakes on all the time. So just remember to not use engine brake or cruise control on slippery roads.

Whenever you touch the regular brakes or the pedal it will automatically go I to gear but is very smooth you won't even notice it. What get lots of driver is the E Coast. It will go in to nutual and cost even on the smallest hill. But if you have the cruise control set it will kick back into gear to turn on the engine brakes and downshift a gear if needed to hold the truck back. It seem very weird to hear and see the egine at idle driving down the road.


A big thing nobody knows about the DT12 has a special Descent Mode for going down big hills. It will hold the truck at the speed you set and the gears. You hear lots of drivers saying they can stop it from shifting gears going down hill.

What you do is turn the cruise control on. Set the engine brake to level 1. Use the regular brakes to slow down to any speed you want. Here the fun part people mess up. You take you foot off the brake pedal and set the cruise control. This will lock the cuise control for the speed your going. The engine brakes will come on and hold you at that speed. If the truck speeds up the computers will turn on stage two and even downshift a gear and bring the engine RPMs up to 2,300 and turn on stage 3 engine brakes. Descent Mode is a cool thing it can do and obviously you don't what to see that when the roads are slippery. It's a VERY stong engine brake and can hold back a lot of weight without needed regular brakes. It works at any speed above 30 MPH. If it can't hold the truck back you would have to use regular bakes and level 3 manually because you don't want engine to go over 2400 RPMs

 

Engine brake set at stage 1 or 2 will always keep the engine RMPs between 1400-1750. Stage 3 will always keep engine RPMs 1750-2200. It's different in if you turn on stage 3 asking for maximum engine brake that what you get ALL the time while on. The transmission will keep downshifting gears as the truck slower down to always keep the engine in 1750-2200 RPMs. It just keeps slowing the truck down as fast as it can and it won't quit untill maybe 20 MPH. Every time the engine reaches 1750 RPMs it will drop a gear and keep slowing as fast and a strong as is can.

 

It's a different animal, for sure.
When on covered roads... inclines and descents... I always turn the auto feature OFF and put the paddle on manual, giving ME as much throttle to ground control as possible.
The last thing I want is a computer deciding to downshift on a slick road causing a jacknife situation.
I've been in this auto for 250,000 and I'm still not a fan.
They think only about fuel economy. That's it. Not safety.

 

Our local dealer has new '18 with a 500 horse twin stack Cummins with a 13 speed manual. Manuals are not dead.

 

They gave me a 2001 century 15 miles on the odo. Automatic from rockwell meritor.

The truck was tuned correctly by the engineers so that when it's time to shift Im reaching for the non existant transmission shifter on the floor. It's not there and she's shifting correct up or down. Took me only 3 weeks before I stopped reaching.

We were a team truck, husband and wife. We never shut off engine. Poor transmission waited a long, long time to find a chance to dump the buffer in it's overflowing software. Finally it bricks. Just like a windows lite machine blue screening. The result is calling out a tow truck.

Manual says I must shut truck off 30 minutes every 7 to 10 days max. VP had to issue a mandatory order to Dispatcher to give us 5 hours every friday so we can get laundry done and have that truck engine off that long. No more tows.

The transmission had a paddle for manual shifting. Also for mountain work to maintain a certain gear, all week if need be. Any gear, pick it. Start driving. That was one thing that really sealed it for us all. It was a great transmission mated to a 500 plus detriot. There were a few other things in the time of winter where it was necessary for the transmission to endure a couple of really violent jackknifes and so forth on snow, ice and whatever. It did fine. In fact, I think it did better than what was humanly possible when there was a problem and she is sliding off the mountain sideways. The engineers in Meritor Rockwell auto division put alot of thinking into that thing. Then....

I still refuse to allow the transmission to be fully able to decide what to do on ice or snow. Because it has a horrible habit of shifting up. Speed picks up 15 mph and it shifts up again. Now trailer is coming around a little bit. So I stay in manual. Always. #### thing will always shift up the moment there is no pulling to do. Makes sense?

 

The new DT12 transmission is pretty smart. It can detect wheel spin and will reduce power to help avoid a jackknife. If you want to pull the trailer just step on the pedal. Their is no turing off the power to reset the computers anymore. The DT12 has GPS locations of all the big hills so it can shift correctly. I can sense the load on the engine and truck and change the shift points accordingly.

If you listen to the engine in low gears like 1-3 you can hear the engine brake come on between great. The transmission can control the engine. They work together as one. The transmission does not miss gears on hills because it can turn on the engine brake between shifts. Just like it does in gears 1-3 when driving around the parking lot.

The truck and transmission and engine will keep the air brakes applied on a hill or at stop light so you don't roll back. The second the engine and transmission feel you pulling the trailer, the air brakes will release and you just keep driving. It's a pretty slick setup when all the systems work together as one.

 

One thing I don't like about the transmission s it's vvery hard to back a heavy trailer into tight parking spots. I find it does not have the power to push a heavy trailer at idle. So you step on the pedal and it very fine line between CREEP Mode and when the clutch engagement. Same problem when hooking to trailer. You don't seem to have the fine control as with a clutch that you can slip as little or a much as you want. Many time I'm hooking to trailer and I can't get truck to move. Then it let's lose and take off and hits the fifth wheel kinda hard.

 

I had that happen a lot in my 2015 automatic Cummins. Real bad, like stuff flying around the cab. I complained about it to the company shop and they jokingly informed me that the Cummins does not have creep mode; what the factory gives it instead is a feature called "lunge mode".