Exhaust Brake on '99 Monaco Windsor

Is there a foot switch on the floor.??? .. left side below the driver's seat. Both my Monaco coaches had them. The switch turns the EB on and the foot switch activates it.

If you do not have the foot switch, then you'll have to trouble shoot it. Let us know if there's no foot switch. Pretty simple, and most people do not lube them periodically as is called for, and that maybe is all you need to do.

That said, you might consider upgrading to the PXRB which is a vast improvement to the OEM....I changed mine out in a campground, using simple tools, in about 45 minutes.....Dennis

do you mfg and model of EB
some use air power, from a compressor
might be a bad electrical connection or blown fuse

you could lift the bed cover/hatch and have some body step on the EB foot switch while you watch and listen

just becuse you cn't hear it , doesn't, mean its not working

not all EB are tied to the transmission

mine a 'De-Celerator' is not connected to the trans and will not cause a down shift

Thanks for the replies. I'm not with the Windsor right now . I only saw the one floor switch to the left of the brake peddle. Didn't look under the drivers seat for another. No switches on the dash that I can find.

I don't know the mfg of the EB, but should be able to locate it and find out.

If you have a floor switch next to the brake pedal, that's probably your activator switch. Should look like a sewing machine type pedal..Dennis

The key to your post is that neither the exhaust brake activates nor the Allison transmission downshift toward the pre-select gear. That suggests that you have an electrical issue in fuse, switch, relay (before Allison ECU or exhaust brake solenoid.

But, if it has been inactive for a long time, the exhaust brake could also be seized from disuse/lack of lubrication.

EB's are hard to diagnose in that the tranny will not allow it to activate unless you are coasting in 3rd gear or above. My Windsor only has a foot switch, no dash switch. After you check the fuse check the brake itself for operation. You can do that by applying 12v to the air solenoid located on the passenger side frame rail over tranny. You can trace the air line from the EB to the solenoid.
PacBrake makes a lube for the butterfly shaft and air cylinder pivot. Occasional lube will prevent the Pacbrake from sticking
You can check the foot switch by using a meter to see if the switch is closing.

Actually, all Allison's I have worked on will only cut out of exhaust brake mode as you descend through 2nd gear (lower speeds in second gear). I have been on several 15% plus downgrades and second gear lockup (higher engine speeds in 2nd gear) work just fine.

Your manual should state that the EB will not work below 15mph. To check this get in an open area and go to say 30mph, foot off of the accelerator and press the EB and just hold it down without the brake. Watch the speedo and tach at the same time. You should have had an increase in RPM when the EB activates. The increased RPM will show till the speed reaches 15 then the tach will drop off to idle RPM. If the EB is working, say at 30mph you will feel a definite slow down and see a rise in RPM. Remember the Allison tranny is pretty smart and it won't shift down to a gear that will over rev the engine at that speed. But 1st. I'd check if the arm on the EB is free to move. Just unhook the arm from the cylinder (pin and key) and it should move by hand, if not you have some work to do. Liquid Wrench makes a penetrating lube that works well as does Pac Brake.
Good Luck
Dave

I had the same problem with my foot switch last year. When I checked it with an OHM meter it checked out fine. After several hours of trouble shooting, this is what my problem was. It turns out the foot switch while checking out fine on the ohm meter, it failed under load. Replaced foot switch, problem solved.

MCDDY wrote:
To check this get in an open area and go to say 30mph, foot off of the accelerator and press the EB and just hold it down without the brake. Watch the speedo and tach at the same time. You should have had an increase in RPM when the EB activates.
Dave

Actually, whether the transmission will/should downshift depends on the PRE-SELECT GEAR. If 4th, it might not downshift at 30 MPH. If 2nd, sure, it will.

Now, a good test:

1. Verify that the transmission shift pad (either left window or only window changes from 6th to the pre-select gear-- usually 4th or 2nd or can be anything.

2. Then, if #1 works, use the down arrow to lock the transmission in the gear it is in with the exhaust brake on. This takes the transmission braking out of the equation. Now, turn on the the exhaust brake-- braking HP should increase. Turn it off, back on, back off, back on-- now, you will know whether the exhaust brake is working.