How do you use the jake brake on a truck with an automatic transmission?

I forgot to mention, TURN OFF the cruise control switch in the KW. Otherwise the engine brake won't engage unless you tap the brake. Otherwise it behaves just like a manual transmission. Well.....it is actually a manual transmission. Just shifted by a computer instead of a driver

 

Let the truck do its thing. The computer will not let the engine run at a dangerous RPM. Sounds to me like the jake is doing exactly what the engineers designed it to do.

 

Might want to read this:
New Cascadia Driver's Manual
2300rpm......that's overspeed on the rpm's according to the manual.
So 2200 is ok.

 

I set my Cruz 4 below what speed I want and let it do the work. It will keep it at set speed or 5 above I have the cascadia dd15

 

Actually the manual states this; " Recommended engine braking speed is above 1800 rpm and below the rated speed.
Which confirms what I was told several years back....the new engines can run 2500 RPM coasting in gear (downgrade without throttle). Throttle will not activate until under the 2300 set limit.

 

2 different automatic trucks, never had a problem figuring out how to use my engine brakes, I've gone down Floyd, Eisenhower, Vail at 84,000 and never touched the brake pedal, only let the engine brakes work. If your doing it correctly, with the majority of these automatics, you'll actually be giving the truck fuel because the engine brakes will work too well.

Also, check your cruise control, some of these newer automatics also have a hill descent control, it's a standard feature on M-Drive equipped Macks and I-shift equipped Volvo's. PACCAR has a variation of it, doesn't work as well, but it works. It will scare the bejeezus out of you the first dozen times you use it, but once you get used to it, you'll love it.

As @Dockbumper said, if it's a KW turn off the cruise control or the engine brakes won't work, although there is a setting that can be changed for this if you have the correct software.

 

I didn't read every post, but try to use the Cruise control with full engine brakes to control your speed.
(The DD15/DT12 combo makes you turn off the engine brake when you set the cruise, because it handles everything.)
As you come to a downhill lower the cruise speed by 2-3, then let the computer handle it.
It will hold you very close to your original speed setting, adjusting the engine brake level as needed.

If you are too heavy with a very steep hill then disable the cruise and use whatever level of engine brake you need, and maybe a little brake in between.

I love the auto's when it comes to controlling downhill speed. They make it much easier to maintain the speed you actually want instead of having to choose a gear and settle for the speed it gives you.

 

The freightliner DT12 auto is one of the best out there. As mentioned, a good way to descend is to set the cruise 4-5mph lower than you want and the engine brake will come on automatically to maintain that speed.

I put 375,000 on a freightliner with the DT12 and very rarely ever had to touch the brake pedal coming down hills.

 

Winner winner chicken dinner.... Especially since he has no idea what some of the buttons do.