Forum Discussion

k_jensen6's avatar
k_jensen6
Explorer
Dec 27, 2013

Exhaust or jake brake or neither?

How do I know if I have a jake brake, an exhaust brake or is it possible that we don't have either of these? We have a 2001 holiday rambler imperial with an Allison 3000 transmission.

Am extremely nervous going down hills.

Thanks
  • Well since no one told you----if it is working properly, you turn it on, remove your foot from the accelerator, and you will feel it not only slow down but shift down.....Thats basically how it works. When it is turned off only your vehicle brakes slow you down when applied.
  • The "Pac brake" is an exhaust brake and a good one at that. Congrats!
  • Old-Biscuit wrote:
    An 'engine brake' is on the engine and controls exhaust valves opening them.....when engaged you will hear a loud pop-pop-pop sound (just like the semis)
    IMO this is a bit misleading because most MH's have a muffler on their engine brakes, (aka Jake Brakes) and are pretty quiet. Any pop pop noise is hardly discernable.

    Jacobs Company also makes an exhaust brake so both are sometimes called Jake Brakes. If you have an exhaust brake - just call it a Pac brake and no one will be confused.
  • OP: When we purchased unfortunately it came with no manuals. I did find the original sticker from the window however, it says, Cummins ISC 8.3 350hp Diesel engine. It also says exhaust PAC brake (?). The brake pedal says air brake on it.

    The only button I can find on the rig in the driver section says engine brake.

    So if this it, how do we use it?

    Thank you so much for your help.
  • Your other post said you had an engine brake???

    An 'engine brake' is on the engine and controls exhaust valves opening them.....when engaged you will hear a loud pop-pop-pop sound (just like the semis)

    An 'exhaust brake' is mounted in the exhaust system and closes it own control valve to create back pressure in exhaust system (back towards engine).....when engaged you will hear an increased exhaust hiss

    Both types of brakes have to be turned on........usually a button on dash.
  • Tell us what engine you have-- that MAY give an answer.

    If not, easy to describe what an exhaust brake looks like and where to find it.
  • You should be able to hear the jake or exhaust brake when you decelerate. Other than that, check your manuals.