2022 Thor Venetian - Freightliner Chassis - Engine Brake

[Slingoslingo]

If anyone can give some input on how to use the engine brake. This does not have a TAG Axle. 40 feet. I called Freightliner and they were not very much help or as much help as the dealer.

Watched a few videos that helped explain some items.

Question - Stalk or stick on right has Manual and Automatic modes. Dont think I use these going down a hill. I want to use engine brake. Video says click stick down (stalk on right of steering wheel) which green light goes on and shows "High" only. Video says it you can click again to get High-Medium-Low??

I can only get a High reading?? It does slow the rig down going down a pass but on a really steep one I would want Medium at least.

Does it offer this option or just "High"? or do I have to use my manual setting for transmission to help slow?? Confusing.

See attached pic of dash and stalk......

Any help on braking going down a hill with a 40K Lbs rig would help.

Thx.

[Gary RVRoamer]

High-Med-Low or High-Low depends on how the coach is equipped. For example, a Cummins ISB or ISC only have one brake "speed", but the ISL has two and ISX has three. Please define your coach chassis better so we don't have to guess.



If you have only a single brake setting, then you control the braking by downshifting more or less. I would think that automatic mode would target a lower gear, at least 4th and maybe 2nd. You won't get much braking at all in 5th or 6th.


I'm not familiar with the controls on your stalk - what does your Freightliner chassis manual say about their use?

[sanfordturbo]

I have the same set up on my Freightliner XCM chassis.



I have only used the HIGH setting for engine braking. I'm hitting the road this weekend and will see if mine comes with other levels and report back my findings.


While going down steep mountain grades the HIGH setting in AUTOMATIC transmission drive mode does help, but not enough to prevent me riding the brakes manually.


Instead, put the transmission into Manual mode and run down thru the gears until you get the speed you desire.


These controls are not as intuitive as they appear to this driver, so practice MANUAL transmission mode (including activating and deactivating) on a regular road.



I fiddled with the controls in the driveway to get familiar with them, then while sitting at a lengthy RED traffic light, i put it into MANUAL transmission mode and ran up and down the gears to get acclimated.



After that, you should be ready for the mountains.

[DuaneMiller]

You have basically the same chassis that I have...

As you have found out, there are many features and operations that are controlled through that right stalk.

Engine Brake - operated by moving the stalk up and down. Like mine, you only have 2 options for your set up... Off and High, there is no medium or low setting. When you pull down on the stalk it turns on the engine brake. With the engine brake "On" you will notice that the coach will slow down automatically without any assistance from the coach brakes. If you watch the tach, the transmission will gear down, and I'm pretty sure the vanes in the turbo will close to assist slowing the coach as well (someone, please correct me if I'm wrong...). You will also see the icon on the instrument panel turn from white to green each time the brake is working. Also keep in mind, that when the brake is working, your rear brake lights on the coach will also illuminate without you applying the brake pedal.

I basically use the brake when driving in the mountains, around town in stop and go traffic, and when I am approaching an offramp when I intend to exit a freeway. I turn it off when on the freeways so the coach will coast when I release the accelerator pedal.

Automatic/Manual Modes - from automatic to manual, engaged by pushing the stalk away from you toward the instrument panel. Also, to downshift when in manual mode, push the stalk away for each gear you want to downshift to. To upshift, pull the stalk toward you for each gear you want to upshift to. To return to automatic mode, quickly press the button on the end of the stalk.

The best way to explain this is to equate it to the PRNDL settings in a car. Automatic mode is basically the same as D or Drive in your car. The coach has control of the transmission shifts.

In manual mode, its the same as using 3,2,1 in an older car, or +/- in newer cars. In most cases, you get to select the gear your want. If you are driving in the mountains, sometimes, when climbing, the coach tranny computer will begin the lug the coach, or keep the engine RPM's at a slower speed so as not to keep sufficient amount of air flowing through the radiator using the engine fan. To keep the RPM's up and not lug the coach, I shift into manual mode and select a gear to keep the RPM's around 2000 for pulling power and to keep the fan speed up enough to keep the engine at a cooler level.

When descending, I use manual mode to help hold the coach speed without having to ride the coach brakes. Now you will have to stab the brakes occasionally to maintain a safe speed, depending on the grade, because, even in manual mode, the coach will not allow itself to overspeed the engine, and it will automatically shift the tranny to a gear that keeps the RPM's in check.

Performance/Economy mode - You activate economy mode by pressing and holding the button on the end of the stalk. Haven't really played around with that setting. But on the surface, can't really tell a difference between the two modes. Maybe someone else can come along with a better explanation.

Please if anyone reads anything incorrect to what I have stated, please feel free to weigh in. I hope what I have said makes at lease some sense...

[Slingoslingo]

Big thank you to fellow member's (sanfordturbo, DuaneMiller, Gary RVRoamer).

Duane Miller posted some really solid information on how it works. I can confirm I have only one setting as Duane has indicated. No Low/Med and only High available.

Gets frustrating as I had said before. Freightliner was very limited on any information beside go check out a video and seem just frustrated with my questions. The RV Dealer.......Deer in the headlight look??? Almost funny.....

This Forum has helped me greatly as a previous Class C Newbie and now taking the big plunge into the Class A Diesel Pusher Class!

Hope I can be of help in the future and keep learning along the way.

[GCSuper]

Originally Posted by Slingoslingo

Big thank you to fellow member's (sanfordturbo, DuaneMiller, Gary RVRoamer).

Duane Miller posted some really solid information on how it works. I can confirm I have only one setting as Duane has indicated. No Low/Med and only High available.

Gets frustrating as I had said before. Freightliner was very limited on any information beside go check out a video and seem just frustrated with my questions. The RV Dealer.......Deer in the headlight look??? Almost funny.....

This Forum has helped me greatly as a previous Class C Newbie and now taking the big plunge into the Class A Diesel Pusher Class!

Hope I can be of help in the future and keep learning along the way.

There was a discussion recently in the Newmar FB site where a member with the same coach as I have ( 2020 Ventana 4369 ) which has a three stage brake, said his only had one setting. The discussion continued where some had one setting, others had three. 2020 was the first year for the new Freightliner dash and controls so at the time of the discussion most of us didn't have a lot of experience with it. I would go thru all your coach literature and try to confirm exactly what your coach has. With the ISL motor I'm surprised you only have one position.

[Gary RVRoamer]

If the ISL engine is equipped with an engine brake, it should have two brake level settings. If the engine is not so equipped and has an exhaust brake instead, then it would have only one. The Jacobs engine brake is an extra cost option on the ISL engine, though most all coach builders order the chassis with that option.

[Dutch Star Don]

First off, the OP needs to determine if he has an engine brake or exhaust brake. I know that Freightliner uses several variations specified by the RV manufacturer. My old Diplomat had the 400ISL, but Monaco only offered the Diplomat in an exhaust brake configuration. Step up one level to the Camelot with the same engine and you got an engine brake.

On my current Freightliner, it has a three-position engine brake that works with the cruise control. It does several different things that took a while to learn.

If the OP has an exhaust brake, he needs to know that the engine RPM needs to drop for the exhaust brake combination (exhaust brake and transmission) to downshift. It won't downshift if the engine speed is too high. Consequently, you need to "stab" the brakes several times to get the RPM's down so the Allison will downshift. The Allison will never allow the engine to overrev.

So, let's say you've got the exhaust brake engaged and you're in 4th gear. If the coach starts picking up speed, which increases RPM's, the Allsion will upshift to keep the engine from overrevving, that's why you need to apply the foot brakes to get the speed down. The best way is to be aggressive at the top of a grade and slow way down, so that the exhaust brake can start working early.

[DuaneMiller]

Here is the section from the FL manual that describes what it calls the "Engine Brake", however, in another section of the manual it mentions "Exhaust Brake" as well. At the end of the day, the outcomes should still be the same... to slow the coach.

As for what one has installed on their coach regarding the various intensities (Hi, Med, Lo) or just (Hi), the stalk sort of dictates that. In my case, I can only pull the stalk down one (1) click. If there are other intensities, then the stalk, at least according to the diagram, would have additional clicks for the other choices. Not sure how that is handled in the older versions with the touchpad.