Understanding & Using Automatic Smart Exhaust Brake

[tmcIlwain]

I want to pick your brains on better use the Automatic Exhaust Brake (AEB).
(BTW I always use Tow/Haul and normally use the EB in the normal [yellow icon] mode)

So far I have found that the AEB works very well if when I start downhill and brake or slow to the desired speed, then remove my foot from the brake pedal, the AEB works well to downshift and/or use the EB to maintain my speed.

What other uses are there for the AEB?

The manual provides the following information:
Automatic Exhaust Brake technology delivers smoother,
less aggressive exhaust braking characteristics during
downhill descents. Although it can apply full exhaust
braking force if needed, Automatic Exhaust Brake may
not apply obvious braking if the vehicle speed is not
increasing. Automatic Exhaust Brake is intended to maintain
vehicle speed, while Full Exhaust Brake is intended
to reduce vehicle speed.

TIA
Tom

 

[Jumbo Jet]

I understand that your brake lights are appreciated by those following you while using AEB and not so much while using FEB.

 

[jacknife]

Owning and driving big rigs for a long long time . Just remember when roads are slick amd you are towing try to minimize exhaust brake on FEB. Your trailer could start coming around if you are not applying trl brakes lightly to keep it going straight. Once the trl passes a 15 degree angle relative to the tow vehicle you are basically screwed!

 

[Dieselnerd]

Owning and driving big rigs for a long long time . Just remember when roads are slick amd you are towing try to minimize exhaust brake on FEB. Your trailer could start coming around if you are not applying trl brakes lightly to keep it going straight. Once the trl passes a 15 degree angle relative to the tow vehicle you are basically screwed!

Good info Jacknife, I often hit icy roads when towing to AZ in December. When towing my fifth wheel I like the full exhaust brake. When the roads are slippery I turn the EB off for the reasons you gave. Did you choose the user name Jacknife because you have some experience with jackknifing?

 

[Wingate]

I run T/H and FULL(yellow light) when towing the camper. No chance of ICE where I live. when running around unloaded, I run Green and no T/H. Wish I could find a place to default the EB to Green on startup.. its a nuisance.

 

[RikDavis]

In smart brake it will downshift if you tap the brake pedal for a little more deceleration. It seems to hang all through the gears instead of dropping when the torque converter drops out because of no downshift in the normal EB mode. This of course is with tow haul engaged. My first EB and I really like it

 

[Gonzo 1066]

I have owned my 2013 for just a year now and have finally tried the "Smart Brake" Steep decent at about 28,000# combined weight.. Tapped the brakes and the EB held us at 41-43MPH all the way down. It was turning the EB on and off, shifting down or up as needed. VEARY COOL how it intigrates to make steep down grades more manageable ...

 

[rrl989]

Using my 2014 AEB for the first time under max GVWR load in the White Mtns, NH. Miles of 8% grades down maintains my last braking speed. Had it locked in at 35-40 mph. Really never had to touch the brakes the entire twisty ride down. The full EB is too aggressive even at 14,000 lbs and 8% grade slows the truck down to a point where I have to hit the accelerator. I'm really impressed coming from a 98 CTD DRW where I've smoked the brakes a couple of times in the past.

 

[Jumbo Jet]

I normally run with the EB switched on all the time unless the road is icy. Just for fun once on an icy down hill street, I switched on the exhaust brake at about 40 mph and let off the accelerator to engage the EB. I already knew what to expect and was just practicing my skills. The back end made an attempt to come around and I steered out of the situation. I learned about driving on ice and snow when I was a teenager 50 years ago. No ABS etc.

Another time, you should have seen the face on the watchman when I entered the ice covered company parking lot and did 3 donuts with my RAM!

 

[Steve Martin]

Helo All, I noticed on my truck that the EB doesn't come on if I’m driving under 30 MPH. I have towed my 5,500 lb. down a steep grade with lots of turns (speed less the 25-30 MPH) and never had the EB come on. I have TH on and transmission locked in 1st. or 2nd gear with EB in the "full on" position (not auto). Not sure if I have a problem or if its design not to come on under 30 MPH. If the EB comes on higher then 30 MPH it will stay on below 30 MPH, but if my speed is less then 30 MPH and I let my foot off the accelerator EB still won’t come on. Someone once told me it’s a RPM issue, so I tried to keep the RPM’s above 1,000 and the EB still wont come on below 30 MPH....Any thoughts???? May need a re flash not sure what’s normal. Can someone check their truck and see if you get your EB to come on when your speed is less then about 30 MPH?? Thanks Steve

 

[tmcIlwain]

Gee Steve,
I'm not sure... All I that I can tell you is that my EB kicks out when my speed gets down to about 20 mph. And I've never seen it work in 1st gear.
With my 2002 manual I could keep the EB on in all gears and down to stall in 1st if I wanted it.
I'll be interested to see other replies to your question.
Tom

 

[Steve Martin]

Thanks Tom,
Just wanted to see if others can make their EB come on under 30 MPH. The only reason I ask is when I tow my trailer down a steep slow grade when you can’t go over 25-30 MPH I get no EB help. Not sure if this normal or not....Thanks for the reply Tom.

 

[BOOTUCKER10]

Ram exhaust brake failure to engage

I HAVE HAD THE SAME PROBLEM .. I TRY TO KEEP THE ENGINE RPM UP ABOVE 1100 RPM BY CHANGING THE GEAR SELECTER TO A LOWER POSITION .. I I have had a situation where I was starting down a steep slope from the top and as I changed the selector to higher gear on the way down , it just increased the engine rpm without engaging the exhaust brake ????

Helo All, I noticed on my truck that the EB doesn't come on if I’m driving under 30 MPH. I have towed my 5,500 lb. down a steep grade with lots of turns (speed less the 25-30 MPH) and never had the EB come on. I have TH on and transmission locked in 1st. or 2nd gear with EB in the "full on" position (not auto). Not sure if I have a problem or if its design not to come on under 30 MPH. If the EB comes on higher then 30 MPH it will stay on below 30 MPH, but if my speed is less then 30 MPH and I let my foot off the accelerator EB still won’t come on. Someone once told me it’s a RPM issue, so I tried to keep the RPM’s above 1,000 and the EB still wont come on below 30 MPH....Any thoughts???? May need a re flash not sure what’s normal. Can someone check their truck and see if you get your EB to come on when your speed is less then about 30 MPH?? Thanks Steve

 

[kthaxton]

It could be that the torque converter has unlocked, which prevents the EB from working. Sometimes you have to goose the throttle a bit to get the rpms up and that locks it.

 

[BOOTUCKER10]

I agree on locked rotor .. sometimes when I use the EB , it steps down until it gets to first gear .. works better on flat . I've talked with others who have similar experiences . I wonder if the asin is better .. I have the ram transmission .. thanks for feedback ..

 

[Cummins12V98]

TH and EB full ALL the time. I run in the high 2K RPM's with cruise on descending a grade. Holds the sped I wan well. if it creeps up I just touch brakes and hit resume.

 

[Newsa]

My 2013 only has yellow EB. No green. It just flashes me a smart brake message if i hit the button twice.

 

[grabinov]

Owning and driving big rigs for a long long time . Just remember when roads are slick amd you are towing try to minimize exhaust brake on FEB. Your trailer could start coming around if you are not applying trl brakes lightly to keep it going straight. Once the trl passes a 15 degree angle relative to the tow vehicle you are basically screwed!

Boy did this happen to me on the way down from Mt. Baldy recently. It's a long downhill with one stretch of road with switchbacks which drop to just a few miles per hour. I was on the way down when it started to sleet on the already wet road. I had Tow/Haul and the Exhaust Brake on as I often do. As I braked into the first switchback on the slippery road, the trans dropped a gear and the EB came on. From what I felt I'd say the combination literally locked both back wheels. The truck got sideways and I sure couldn't hope to power out of it going downhill on a slippery road into a 5 mph hairpin turn. I turned into the slide (and into the oncoming lane - luckily no traffic) and hit the brake. I didn't have a lot of other options. Luckily the truck stopped (front wheel ABS) before I steered into the mountain, but, as I said, I didn't have a lot of options.

I've been driving a long time, and I am an engineer by training and generally pretty saavy about things automotive, but I have to admit, it had not occurred to me that this would happen. In a modern truck with ABS (granted, it's for braking) you just don't imagine that the electronics will let you lock up the rear wheels simply by your choice of drivetrain settings (Tow/Haul, Exhaust Brake). Isn't the ABS sensor on the rear wheels connected to the drivetrain control module? Doesn't it know that the wheels were locked by it's shifting and EB action? Shouldn't it release the exhaust brake and "undo" the down shift?

I guess there is no Downshift or Exhaust Brake "ABS" in the software...

 

[Newsa]

Boy did this happen to me on the way down from Mt. Baldy recently. It's a long downhill with one stretch of road with switchbacks which drop to just a few miles per hour. I was on the way down when it started to sleet on the already wet road. I had Tow/Haul and the Exhaust Brake on as I often do. As I braked into the first switchback on the slippery road, the trans dropped a gear and the EB came on. From what I felt I'd say the combination literally locked both back wheels. The truck got sideways and I sure couldn't hope to power out of it going downhill on a slippery road into a 5 mph hairpin turn. I turned into the slide (and into the oncoming lane - luckily no traffic) and hit the brake. I didn't have a lot of other options. Luckily the truck stopped (front wheel ABS) before I steered into the mountain, but, as I said, I didn't have a lot of options.

I've been driving a long time, and I am an engineer by training and generally pretty saavy about things automotive, but I have to admit, it had not occurred to me that this would happen. In a modern truck with ABS (granted, it's for braking) you just don't imagine that the electronics will let you lock up the rear wheels simply by your choice of drivetrain settings (Tow/Haul, Exhaust Brake). Isn't the ABS sensor on the rear wheels connected to the drivetrain control module? Doesn't it know that the wheels were locked by it's shifting and EB action? Shouldn't it release the exhaust brake and "undo" the down shift?

I guess there is no Downshift or Exhaust Brake "ABS" in the software...

On the roads covered with pure ice, 4x4 won't help. But this is why i got the 4x4.

 

[kthaxton]

Boy did this happen to me on the way down from Mt. Baldy recently. It's a long downhill with one stretch of road with switchbacks which drop to just a few miles per hour. I was on the way down when it started to sleet on the already wet road. I had Tow/Haul and the Exhaust Brake on as I often do. As I braked into the first switchback on the slippery road, the trans dropped a gear and the EB came on. From what I felt I'd say the combination literally locked both back wheels. The truck got sideways and I sure couldn't hope to power out of it going downhill on a slippery road into a 5 mph hairpin turn. I turned into the slide (and into the oncoming lane - luckily no traffic) and hit the brake. I didn't have a lot of other options. Luckily the truck stopped (front wheel ABS) before I steered into the mountain, but, as I said, I didn't have a lot of options.

The owner's manual warns of this. It is also a thought that had not crossed my mind until I read it, but it makes perfect sense.

I've been driving a long time, and I am an engineer by training and generally pretty saavy about things automotive, but I have to admit, it had not occurred to me that this would happen. In a modern truck with ABS (granted, it's for braking) you just don't imagine that the electronics will let you lock up the rear wheels simply by your choice of drivetrain settings (Tow/Haul, Exhaust Brake). Isn't the ABS sensor on the rear wheels connected to the drivetrain control module? Doesn't it know that the wheels were locked by it's shifting and EB action? Shouldn't it release the exhaust brake and "undo" the down shift?

I guess there is no Downshift or Exhaust Brake "ABS" in the software...

The wheels aren't actually locked though, they are just suddenly going significantly slower than the road speed. This same exact scenario would happen if you shifted down hard on any slick surface even without an e-brake.