This video shows you how to properly operate a truck with a new DT12 in a steep downhill situation, protecting the truck from over-speed damage. The training in this video is applicable to the new Freightliner Cascadia.
I've driven several Freightliner trucks equipped with the DT12 transmission and in my opinion by far the best way to operate this transmission going downhill is to use manual mode and the engine brake to keep speed under control. I've also had loads grossing upwards of 80,000 LBS and a properly functioning engine brake is usually sufficient to keep speed in check with minimal service brake application. There are some companies that have chose to lock out all modes except for auto economy. One company i drove for was like this and I stayed at that company for about 6 months. I left that company primarily for that reason as I felt very unsafe in not being able to slow the truck down on ice and snow covered downgrades.
Im driving a truck locked in eco mode right now and am trying to find anyway to make it climb hills better even when u make it downshift till only hold rpm for 30 40 secs before shifting back to highest gear and i hate the coast gear as well its sketchy as hell
@@jpugh3076 Yep. That is called Detroit Diesel Intelligent Powertrain Management. I hated it also. Just wait until you have to deal with a snowy mountain downgrade with that shit. You have very little control over the engine and transmission. It is up to each company that buys the trucks whether to have that activated or not. The DT12 transmission without that shit activated is fun to drive.
DD series engines tend to spin bearings more often than Series 60 engines. A DT12 equipped truck is more likely to spin the bearings than one equipped with a manual.
Our company is going full auto, and our old 2017 Cascadia 10 speed was retired. I now have a 2020 Cascadia , auto and hate the way the engine brake works. The high rpm scared the shit out of me. I thought it was going to blow up Haha. Glad i found this video. Now i know 2000+ rpm wont kill the engine lol
On all engines you're supposed to be as close as possible to the maximum engine speed for maximum retarding power. According to Jacobs Enginge Brake: "Best retarding performance is obtained at engine speeds between 2100 rpm and high idle. Below 1700 rpm, retarding power may be significantly reduced." www.jacobsvehiclesystems.com/sites/default/files/2018-08/Jacobs%20Engine%20Brake%20Operators%20Manual.pdf More specifically, retarding power for the DD15: 2300 rpm = 538hp 1900rpm = 439hp 1500 rpm = 321hp 1100rpm = 145hp parts.jacobsvehiclesystems.com/files/support/docs-pdfs/Sell_Sheet_DD_721_2.pdf
In 2023 I can tell you that a AMT equipped truck is more likely to spin the main bearings than a manual one. The Ecoast mode on AMT trucks can result in inadequate oil flow for lubrication on high mileage engines.
This engine & transmission are very nice, but the best and safest way to take a long grade is still to put it in manual and choose the gear/engine brake level yourself. Carriers should be encouraged to hire responsible drivers and train them to drive the truck, and not just disable manual mode and have the truck essentially drive the driver.
I been driving a truck with a DD16 600hp automatic. This thing has good power and a strong engine brake. I use mine around 2000rpm. Been driving 20 years don’t miss a manual. Less work for me. Drives like a car.
Empty trailer leave it on auto, but with load set it to manual down shift to lower gear and let engine brake do most of the work, maintain safe speed, apply braking on steep grade along with engine brake. If your brakes catch fire, fire extenguisher will not put it out be sure to have plenty of water bottles.
This truck resembles a Mercedes S500. After some research. I found out Daimler AG owns Freightliner. They also own Mercedes! The dashboard screen & shifting gear are from European Mercedes semi trucks! So technically this semi is a Mercedes! Is just missing the badges! I’m going to put Mercedes badges on mine. Lol
NC Styles Mercedes-Benz engine, transmission, steering wheel, buttons, cluster. The problem is what it’s still a Freightliner, uncomfortable and uncontrollable...
We thought this was a good idea but really it’s not. So, you are ultimately responsible for the speed of the truck. Gee, thanks brilliant engineer guy.
It’s so god damn annoying. Constantly pressing the brake even with cruise set. I can’t be driving 67 downhill in a 60.... the engineer responsible for this needs a slap in the face.
I have a 16 Cascadia with a 10 speed auto. I haul heavy 80000 most loads. I got a steep hill 2lane road with a 15 mph off ramp At the bottom I'll start down shifting in manual at the top and I'll run about 35 mph off it 7th gear. If I'm not careful when I switch bake to auto. It will PEG out at 2000 rpm. It's a rare Cascadia I think I'm Running an ISX. and tis is my first truck with a Jake brake as well.
Yeah kinda tru about the rpm speed. My question is how long it can stay at 2300 RPM before engine stops and I have to park at the side of the road waiting for a tow truck. Personal experience I've done 2400 RPM down hill. I just make sure I slow down to 1500 before letting it rise again to 2400.
@@mikezunker I loved my Cummins X15 until it left me in the middle of the Mojave desert at 2am with a blown fuel pump. 3500 dollars later got a new fuel pump and drove 100 miles exactly before it blew the fuel line attached to the new pump. Dead for another day because that fuel line was on national backorder so we had to get a shop to manufacture a fuel line for it out of hydraulic hoses and connections. It was a great engine until that point. At high RPM going down the steep grade that's like 15 miles long the fuel pump exploded. Cummins don't like RPM.
They should protect that engine if it's an automatic, let's say by automaticly applying the brakes at a certain level for example 30% until reaches 2100 rpm however only in summer time activated by button.
Or how to blow up an engine early. If you keep the RPMs below 1500 at all times a DD15 engine can go further than 1.2 million miles, that is if you properly maintain your power train.
,Manual the truck and lower one gear before going downhill, apply engine brake RPM should go from 1700 to 1800, not go above it and Use the service brake comfortably, do not press it too much,If Rpm goes up to 2500 then all warranty of the truck is void
@@dufonrafal not true, at higher RPM's you have less engine compression, you will over speed, slow the truck and upshift one gear, 1700 rpm in the right gear will do the trick, but you need to slow down.
@@dufonrafal do what feels right, I run I 70 through the mountains of Colorado weekly, been doing it for decades, I've never roached my brakes, just saying....
Downhill 7% in the snow,. Ride the Brakes?! Wtf!!! Or it over compensates with intermittent full Jake., I almost lost it! 1st time in 20yrs even close to a jack. The Coq has never scared me until tonight!!!
Yeah kinda tru about the rpm speed. My question is how long it can stay at 2300 RPM before engine stops and I gave to park at the side of the road waiting for a tow truck. Personal experience I've done 2400 RPM down hill. I just make sure I slow down to 1500 before letting it rise again to 2400.
Not a good model year. Chrome trim blinds you (use car wax to haze) and solar panel tech display unreadable in sunlight forcing operator to depend on sound anyway. Too distracting second guessing some shifts, mostly kept in manual testing. Default granny gear annoying, constantly double clicking to upshift. Drive/Neutral/Drive in combination with proper braking faster than down shifting with 2 double clicks. Climbs in auto okay, downhill, not as good. Most probably will not care. As new drivers race passing at 1 mph this is a waste of time trying to use transmission to save fuel my opinion. Helps avoid freight shifting possibly. Also what gear you are in is what really stops the truck in most conditions, gears are lubricated, brake pads are not. That's why newbies catch tires on fire.
Do you know when I know freightlineris is not American made truckTruck everything assembled in Mexico and that’s a guarantee because I go to the border and deliver them to the dealer
the programers or this transmission need to fix this automatic downshifting while the jake brake is on. your either maxing out the rpm of the engine or to low of rpm to do you any good, this is the stupidest programing i have ever seen on a transmission. very difficult to get down steep grads without overspeeding the engine
@@Nvaillancourt You think it's a piece of shit because you do not fully understand how to use this transmission. If your company has locked out some modes then it is going to be difficult to use. The first time I used one I was apprehensive about it but the first time I was able to downshift going down an 8% grade in North Carolina I was sold on it. The company I drove for then did not have any modes locked out and i was able to explore all of the functions of this transmission. It is a fun piece of equipment to use. OTR driver since 1988.
The cascadia is not good air conditioning no good the radio 📻 is shit the automatic has a lot problem with the warnings codes I recommend buying other type of truck
I read the owners manual the other day...it said the best rpms for engine braking are about 1,800 or 1,900 I beleive..it said anything less will significantly reduce the engine braking effiencinecy... that being said I've never let mine go past 1,700 either..but I'll try it next time...c-15 accert
@@jmh4ggg I've always lugged mine down to about 12-1,300 going uphill then downshifted a whole gear. Half gear I shift around 1,400. I read my owner's manual after I read your comment and mine says to lug it down to 1,100 and not to run it past 1,650 as the torque curve sky dives after 1,700. 2006 C15 625
@@dant387 I'll go down to 1,200 when I'm climbing and I know I have to downshift, if I'm at the Crest of a hill I may lug it down to 1000....but regular driving I always keep it between 1,100-1,500 period...I was only talking about engine braking...I only let it get past 1,500 I'm going down a mountain and engine braking, and then I'll keep it at 1,700 or less...I'm going back to work next week...ill see what taking it past 1700 engine braking will do
Hey Lee i am with you 10 .13 18 is better i think all drivers need too drive both stick shift and automags .my dad first truck was a 1962 H model mack with two gear sticks a 15 speed tranny he never missed a gear.the knew trucks are great but they have big engines 400 450 500 550 hp but they set the computers at 62 68 mph.i talk too the man at the mack dealer in Allentown Pa.all truck dealers i talked said we will set your truck too run like you want it too .
Максимальные значения оборотов на ДД12 и их семейства при использовании моторного( горного) тормоза 2100-2300 об/мин крутить двигатель 2500об/мин запрещено!Чем круче спуск тем ниже передача...При увеличении оборотов выше 2300об/мин необходимо применять основную тормозную систему... кратко основные моменты...
freigtliner and detroit diesel owned by mercedes benz(daimler benz), detroit and mercedes om series engines have same engine block,and mack owned by volvo too,soo many of american trucks not american,and bad news is engine brake is old and bad tecnology for braking ı dont understand why american trucks dont using retarder in 2020 lol its standart in europe
American trucks have had “ Webasto” for almost 20 years. The truck doesn’t have it if the owner doesn’t order it from factory or doesn’t have it installed by the dealer. I have a thing called Park Smart in my Cascadia that uses webasto for heating and air conditioning for cooling the sleeper. It runs on batteries and I have 4 additional batteries and when using the a/c it in the summer, it will run for up to 15 hours
Where? I wanted to drive manual but nobody had one for me to test on and now I have a restriction on my CDL. All the big fleets are automatic. Industry's changing, get over it
All these crazy ideas just to sell trucks. Promising better fuel mileage at the cost of burning up Brakes and possibly hurting someone trying to stop the truck...Dangerous
I've been driving autos for 6 years and never burned up my brakes. I've taken grossed out trucks down 9% grades and barely had to touch service brakes. You have to know how to drive these new trucks. Get your speeds under control and these autos will do a great job of keeping you from going too fast.
@@brandonhebert5485 Can I get some advice please? Ill pay money at this point. You use manual mode? Do you apply the brakes to bring it down 5mph if it speeds up too much? How long do you wait between using the service brakes ? One driver I was with kept turning the engine brake off and snubbing the brakes hard for 1 second to maintain speed, then engine brake on again. And we went through one very long Utah downhill at 6-7 percent grade. We literally couldnt get the speed below 75 mph. It was an 80mph speed zone. He said its impossible to take that downhill under 75mph. Does this make any sense? Im in a 23 freightliner.
