2020 dd15 dt12 reviews from experienced drivers?

I like it. I've driven them since the 2016 model I drove for a while. Then drove a 2018, then a 2022 model. Once you go automatic, you'll never go back. Sometimes they can do some wonky shifting but they have a lot of that ironed out now. The 16 was way worse than the 18, and the 18 way worse than the 22. As time has gone by they've gotten much better.

It can haul whatever the truck can handle. It's not an automatic, it's an automated manual. Meaning its a 12 speed manual that has all the gadgets and gizmos to shift it for you at the optimum time to maximize fuel mileage. It's not the same as a 4 wheeler's automatic tranny with a torque converter.

If you don't drive for a mega it will have E mode and P mode. P mode wakes it up a bit and lets it shift at higher rpms and into different gears than it would in economy mode. If you're at a mega you'll be locked into E mode so it will be sluggish.

 

I’ve heard of some DT12’s destroying engines.
Driver goes down a steep hill, puts it into low mode which makes it aggressively downshift to help hold on the speed on the hill in conjunction with the jake brake.
Driver never bothers to use the brakes to maintain speed, truck picks up too much speed, transmission doesn’t upshift, motor over-revs. Seen some as high as 2800 rpm. Engine starts throwing piston rods.

 

I've never heard of that happening but I believe it. But that would mean they are ignoring the overspeed warnings on the dash. Lights start flashing above like 2200rpm or something. I do like the jakes on the DT12.

Detroit made a video specifically to teach drivers how to use the new tranny on steep downhill grades. They can't MAKE people watch it and learn.

 

I’m in a 2022 and it does so this. Easy solution, use the foot brakes with the engine brake. Plus start down the hill slow and it works fine. One thing is in cruise if someone gets in front of you to close, it will throw the jakes on and down shift. At 65 and going from 12th to 9-10th gear not good. Just gotta be mindful and catch it before hand.

 

I have a 2020 Western Star with a DD15, but I have a 10 speed manual. I had a DD15 in my 2015 Cascadia (also a 10 speed manual). Great engine. Never had an issue with it. The DEF system in the Cascadia was another matter however...

 

We have a 2019 505hp DD15 with the 12 speed and 3.08 rears and its a pleasure to drive in the hills. We run manual mode on the downhills to control speed/rpms and so far I'm really impressed with the thing. Driving the auto is so easy and convenient that I don't know why I even own a manual anymore!

 

What is heavy to you?

 

More importantly, what's a dot transmission?

 

I'm guessing he was typing DT and autocorrect reared it's ugly head.