Exhaust or jake brake or neither?

calewjohnson wrote:
Do these brakes need to be turned off when entering towns that have restrictions stating such, or is that for semi trucks? I have seen that in towns through Nevada and CA.

Cale

Like California with their 55mph towing law, many communities are changing the wording on their signs. Instead of "No Jake Brake", we're seeing more "No compression brakes" or "No engine brakes"...most,if not all those ordinances were written for UNMUFFLED ENGINE brakes not exhaust brakes or muffled engine brakes. They are different animals as they utilize different methods of slowing the coach. Most modern RVs utilize muffled engine brakes so it's a non issue..all they're really asking is that we be considerate of the neighborhoods.....Dennis

calewjohnson wrote:
Do these brakes need to be turned off when entering towns that have restrictions stating such, or is that for semi trucks? I have seen that in towns through Nevada and CA.

Cale

I personally do not believe that they make enough noise to worry about such restrictions. Those laws are written to stop trucks with "Jake" brakes that sound like this. Problem is that their law is often not enforceable because the truck may not have a "Jake" brake. "Jake brake" is a nickname for the Jacobs Engine Retarding systems. Jacobs manufacturers several type of systems such as exhaust brakes, bleeder brakes, compression release brakes. Adding to the confusion, Cummins, Cat, Mack and others also make engine retarding systems. Your exhaust braking system should not make enough noise to get you into trouble. But it may be best to avoid using it in residential or business district areas.

k.jensen

You and I have basically the same coach & drive train with a PAC Exhaust brake. Mine has a foot pedal and a switch on the panel by the tranny controls. Just remember that the engine, tranny and pac brake combo is pretty smart. Maintenance is pretty easy since you have a side radiator and the whole rear opens up for engine access. Keep good lubricants and filters in everything and the coach will give you years of near trouble free service.

Dave

Do these brakes need to be turned off when entering towns that have restrictions stating such, or is that for semi trucks? I have seen that in towns through Nevada and CA.

Cale

" You can stop by your local Cummins or Allison dealer and they will look over your coach and advise you what exactly you have and how to use it properly."

THERE is the best advice I see in this thread! Go to the local experts for some hands-on teaching!

A word of caution...the exhaust brake should NOT be used in rain and/or snow. Also, usually it will not engage if the cruise control is ON.....

To the OP...when descending a grade, engage the EB as your speed picks up...the brake will engage and the shift PANEL will show 2,3 or 4 depending on how your rig is configured. (a simple adjustment can be made to the computer to change it to whatever gear you're comfortable with) but the tranny may not shift down immediately. If it does not, and you are still picking up speed, hit your service brakes by jabbing the pedal..this will usually cause the tranny to downshift and your coach will slow. Once you get the hang of it, you will rarely use your service brake going downhills. Just remember to use the jabbing method on the brake pedal. You can stop by your local Cummins or Allison dealer and they will look over your coach and advise you what exactly you have and how to use it properly....Dennis

We KNOW that the OP has an exhaust brake.

No Cummins C which he has has an engine compression brake. He also said he has literature in his coach about a PacBrake.

Often the distinguishing factor is the button that turns on the brake device. Most often the exhaust brake is an on/off button, and if there is a two stage button it is a Jake (Jacobson) brake. Both are intended to slow up the vehicle and I would encourage you to get acquainted with this device. Generally, we have found the Jake to be more aggressive even in the less aggressive mode in slowing the vehicle up. I have taught RV safe driving in just about every brand, size, or vintage RV motor home. You have two valuable tools to slow you up coming down a mountain as an example. The Allison 3000 can take some speed off by just shifting down. You can't break the transmission because the computer logic won't let you Do use the transmission down and/or the engine braking devices. They will help control the speed on a down hill but you will most likely still have to use the brake to keep you from losing control. One other note, you can leave either of the engine retarders on all the time. Enjoy your RV and safe driving!

On our '97 Dynasty we have a PacBrake. Ours does not have a switch to turn it on or off. When I need additional braking power, I remove my foot from the accelerator and push the Pacbrake switch with my left foot (it is on the floor right next to the dimmer switch). Just removing my foot from the accelerator does not produce any additional braking power.

To use the exhaust brake......turn it on
When you let off the accelerator pedal it will engage (closes...has some method of regulating exhaust back pressure) and you will decelerate. Your Allison transmission will probably downshift also slowing you even more.

When you push on accelerator pedal the exhaust brake will disengage (open) until you let off pedal again.

Great for downhill as it will help slow/control downhill speed.

Turn it ON when you want to use it....turn it OFF when you don't

I use mine whenever towing
I even use it sometimes when not towing
Simple.......push the button

Try it out...see how it works.