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Old 11-06-2021, 08:54 PM   #1
MSK
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Exhaust Brake Usage

Just a general question. Many Class A units have an "exhaust brake" switch that is recommended for use when towing or going down hill. In general it downshifts the transmission in order to use the engine compression as an additional braking component. Clearly this puts some additional wear and tear on both the engine and transmission and my question is: Is there a good reason not to engage this capability during all operations? In my case I have a Freightliner chassis equipped with a Cummins diesel engine and an Allison 6 speed automatic transmission. This is a robust power pack designed and manufactured for long haul, heavy duty use. I rarely put more than 5K miles a year on my rig, so I don't think that the additional wear and tear would be a factor over the life of my ownership.

I am interested in any thoughts or experiences.

Thanks

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Old 11-06-2021, 09:40 PM   #2
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Use it...no downside. That is why it is on every long haul truck in America. Especially on long downhills. Without the jake brake you could easily experience brake fade---( brakes and fluid get too hot to actually work.)
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Old 11-06-2021, 09:46 PM   #3
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Use it.

It would take 100 years to begin to put enough wear on it to matter. And even then the engine is not putting out power when braking, it is absorbing power- a fraction of what it is capable of putting out.

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Old 11-06-2021, 09:50 PM   #4
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Watch for road signs against it,
Use it all other times.
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Old 11-06-2021, 10:17 PM   #5
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Watch for road signs against it,
Use it all other times.
Up here the only signs are for unmuffled which at least my RV is muffled.
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Old 11-06-2021, 11:25 PM   #6
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Watch for road signs against it,
Use it all other times.
Typically that's referring to Jake Brakes which is an unmuffled exhaust dump equipped on semi tractors that rattle like a machine gun, not the same in motorhomes or diesel pickups, those signs do not apply to RVs or pickups unless the exhaust has been modified.
If you turn the key to start the engine engage the exhaust brake & go!
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Old 11-06-2021, 11:31 PM   #7
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Typically that's referring to Jake Brakes which is an unmuffled exhaust dump equipped on semi tractors that rattle like a machine gun, not the same in motorhomes or diesel pickups, those signs do not apply to RVs or pickups unless the exhaust has been modified.
If you turn the key to start the engine engage the exhaust brake & go!
Wrong, typically it is how the sigh reads “Exhaust Brakes Prohibited” RV Exhaust brakes are classified exhaust breaks.
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Old 11-06-2021, 11:35 PM   #8
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Those exhaust brake signs are usually posted in a city or town where they want it to be a bit more on the quiet side.


Paul
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Old 11-06-2021, 11:37 PM   #9
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Wrong, typically it is how the sigh reads “Exhaust Brakes Prohibited” RV Exhaust brakes are classified exhaust breaks.
Not in the Northwest - at least in the eastern parts of Oregon,Washington and of course Idaho. In some little towns they say just say no Jake braking but most have unmufflered jack brake. Sure have never had any issues out west.
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Old 11-07-2021, 12:01 AM   #10
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Originally Posted by MSK View Post
Just a general question. Many Class A units have an "exhaust break" switch that is recommended for use when towing or going down hill. In general it downshifts the transmission in order to use the engine compression as an additional breaking component. Clearly this puts some additional wear and tear on both the engine and transmission and my question is: Is there a good reason not to engage this capability during all operations? In my case I have a Freightliner chassis equipped with a Cummins diesel engine and an Allison 6 speed automatic transmission. This is a robust power pack designed and manufactured for long haul, heavy duty use. I rarely put more than 5K miles a year on my rig, so I don't think that the additional wear and tear would be a factor over the life of my ownership.

I am interested in any thoughts or experiences.

Thanks
The old Jake Brake was strictly a compression brake and often on straight pipes. Most modern rigs have a two or three position switch that closes off fuel to a certain amount of cylinders and lets the engine become an air compressor basically slowing down the vehicle

The ECM and transmission module determine what gear is selected based on rpm's and speed

Yes use it and don't run with it on unless you verify it doesn't engage your brake lights

I use mine for almost all of the braking needed to slow down to conserve brakes and also have it readily available by being on incase i have to stop quickly
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Old 11-15-2021, 01:39 AM   #11
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Anything with DEF does not have a Jake Brake. They now change the vanes in the turbo's to slow the rig down and may use other methods. I use it 100% of the time. I have a 2013 with drum brakes and it makes a huge difference with stopping distance.
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Old 11-15-2021, 02:11 AM   #12
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Questioni have a 2019 e450 with a tow button on the steering. When going up or down hill I push in even when not towing?

I notice going down hill it helps with braking is this ok?

Thx
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Old 11-15-2021, 02:29 AM   #13
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Questioni have a 2019 e450 with a tow button on the steering. When going up or down hill I push in even when not towing?

I notice going down hill it helps with braking is this ok?

Thx
Yes it does, and that's what it's for. I have that on both our Ford class C, and on my 2017 F-150. I use it in the MH even when not flat towing the Jeep.

I use it all the time when traveling through West Virginia. When you start applying brakes downhill, it downshifts fairly abruptly and the engine really screams... but that's normal. It's using the back pressure from the engine compression to help slow down.

It saves cooking the brakes. BUT, mine sometimes gets carried away and doesn't upshift quick enough at the bottom of hills going into a level stretch. To "help it along", I goose the gas a couple times, which usually works.

Sometimes I use the tow/haul in sort of a manual fashion. I push the button when I see a sign warning of a long descending steep grade. I let it do it's thing - downshifts and all. Then, at the bottom of the hill I push the tow/haul button again to turn it off. That method seems to work best for me... I have better control.
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Old 11-15-2021, 02:41 AM   #14
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116,000 king ranch miles, all tow/haul.
26,000 e450 miles, all tow/haul.

The big block 8.1 Chevy, not so much. It makes it shift too hard for daily comfort.
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Old 11-15-2021, 02:58 AM   #15
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Yes it does, and that's what it's for. I have that on both our Ford class C, and on my 2017 F-150. I use it in the MH even when not flat towing the Jeep.

I use it all the time when traveling through West Virginia. When you start applying brakes downhill, it downshifts fairly abruptly and the engine really screams... but that's normal. It's using the back pressure from the engine compression to help slow down.

It saves cooking the brakes. BUT, mine sometimes gets carried away and doesn't upshift quick enough at the bottom of hills going into a level stretch. To "help it along", I goose the gas a couple times, which usually works.

Sometimes I use the tow/haul in sort of a manual fashion. I push the button when I see a sign warning of a long descending steep grade. I let it do it's thing - downshifts and all. Then, at the bottom of the hill I push the tow/haul button again to turn it off. That method seems to work best for me... I have better control.

Excellent thanks
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Old 11-15-2021, 03:49 AM   #16
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my tuscany has the VGT exhaust device, it does pretty good on highway exits and some moderate hills.



works really well in 2nd gear and 1st



not so much in 3rd or higher. imo


if i need to slow down on a long hill, i use it and stab the brakes hard to bring her back down to my preferred speed.

this way i dont over heat the brakes.



only place i got skeeeereeed was the 160 highway in Colorado headed toward 25
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