Community Forums

ctundra · 11-21-2014, 08:53 AM

have a 2013 HR Endeavor, bought it new. Having problems controlling speed when going down 5 & 6% grades. following suggestions when starting down a steep long grade "shift to low gear, usually 3rd, slow down to 35mph at top of grade turn on exhaust brake", all done prior to heading down. once i get started down and not very far into the grade, speed hits 55mph 2700-2800rpms and trans shifts to 4th, if i don't mash the service brake at this point moho will speed to 65 and then 75mph with trans upshifting to 5th gear. At that point things get out of control requiring very hard mash of brakes to slow the moho down to 60mph and then within a few seconds having to start the same drill all over again. brakes get very hot. recently coming down a long and steep grade between Flagstaff and Camp Verde AZ the moho was almost unmanageable with speeds topping out at 85mph. Having to constantly mashing the brakes very hard to keep speed from going even faster. Not fun at all! Looking in my owners manual it talks about this moho having an Engine Brake and not Exhaust Brake. Crawled under engine and saw there is a PAC Brake installed. Wanting more info on troubleshooting possible problems i called PAC Brake, they said they do not install PAC's on MF 10 engines - even though i can clearly see the PAC exhaust brake installed (deadend with them). called Navistar shop in AZ they could not provide much info withouot first having the moho in the shop to look at (taking it to them when in Tucson in two weeks). called Navistar Tech Support, he explained that all MF 10's since 2010 do in fact have a PAC Exhaust Brake installed primarily used to raise exhaust heat for the Rengen process and not as a typical exhaust brake. He went on to say, however, the PAC could also be used as the exhaust brake if the moho manufacture wanted it set up this way, but could not tell me if it was, said i would need to call Monaco for that info. He said in most cases the Navistar Engine Brake is typically used, this is an internal brake worked off the exhaust valves, kind of like a Jake Brake, but not. i then called Allied Rec Group (monaco) in Colburg, they said according to the moho build sheet it says i have a "turbo exhaust brake" - never heard of that before, we concluded whoever typed the build sheet my have misused the term Exhaust Brake. all this said, the HR owners manual reads nothing of an exhaust brake. so darn confused. asked all the folks i talked to if they are getting any similar complaints, none before me. i also have a tow brake system in my jeep GC tow car, have this cranked to the max and still having hard time controlling speed down grades. Anyone else having issues or suggestions would be helpful? thanks

Ray,IN · 11-21-2014, 09:09 AM

The turbo "brake" is actually a variable-vane turbocharger, that reverses the vanes to pull a slight negative pressure in the combustion chambers. A PAC brake would help that.
Check the PAC brake for proper operation, if it is not functioning properly it must be repaired, usually by freeing-up the butterfly valve in the exhaust pipe or connecting linkage, and lubricating with special high-temperature stuff sold by PAC brake and other companies.

wb7auk · 11-21-2014, 09:24 AM

Using the brakes early to slow vehicle then let up on them so they can cool then apply
again to slow vehicle again, do not ride brakes they need to cool and waiting until your
speed is way up is a accident looking for a place to happen.
Exhaust brakes, and engine brakes are too assist normal brakes not a replacement.

VestaDave · 11-21-2014, 09:50 AM

Can't really offer any solutions except to say take it in as soon as possible. Phone contacts just won't get it done. We have an early 2011 Vesta with no exhaust brake. Our first trip with it was truly scary because on steep grades it would up shift to neutral! At the grade bottom we could smell the brakes. Not good. It actually turned out to be a program issue with the Allison. We don't have an exhaust brake but I no longer feel like we are out of control. The point here is, something is wrong and needs to be fixed.

ctundra · 11-21-2014, 11:42 AM

thanks all for the comments. Not riding the brakes - mashing them as you should. this is not tapping or riding. applying with a steady firm pressure and then getting off the brake as to not cause excessive heat. Although when having to do this every 5-10 seconds for 18 miles, can't help but to heat up the brakes. Hopefully when i get it to the shop they're able to pinpoint the problem. believe there are no more steep grades between where i'm currently staying and Tucson.

my prior experience with 2004 Monaco Diplomat (PAC Brake) did not have issues going down grades, was very easy to maintain any speed with not much service brake action. not to mention no darn 2010 emission thingamabobs hanging off the engine. thanks EPA! not...

Steve Ownby · 11-21-2014, 12:22 PM

Quote:

Originally Posted by ctundra

have a 2013 HR Endeavor, bought it new. Having problems controlling speed when going down 5 & 6% grades. following suggestions when starting down a steep long grade "shift to low gear, usually 3rd, slow down to 35mph at top of grade turn on exhaust brake", all done prior to heading down. once i get started down and not very far into the grade, speed hits 55mph 2700-2800rpms and trans shifts to 4th, if i don't mash the service brake at this point moho will speed to 65 and then 75mph with trans upshifting to 5th gear. At that point things get out of control requiring very hard mash of brakes to slow the moho down to 60mph and then within a few seconds having to start the same drill all over again. brakes get very hot. recently coming down a long and steep grade between Flagstaff and Camp Verde AZ the moho was almost unmanageable with speeds topping out at 85mph. Having to constantly mashing the brakes very hard to keep speed from going even faster. Not fun at all! Looking in my owners manual it talks about this moho having an Engine Brake and not Exhaust Brake. Crawled under engine and saw there is a PAC Brake installed. Wanting more info on troubleshooting possible problems i called PAC Brake, they said they do not install PAC's on MF 10 engines - even though i can clearly see the PAC exhaust brake installed (deadend with them). called Navistar shop in AZ they could not provide much info withouot first having the moho in the shop to look at (taking it to them when in Tucson in two weeks). called Navistar Tech Support, he explained that all MF 10's since 2010 do in fact have a PAC Exhaust Brake installed primarily used to raise exhaust heat for the Rengen process and not as a typical exhaust brake. He went on to say, however, the PAC could also be used as the exhaust brake if the moho manufacture wanted it set up this way, but could not tell me if it was, said i would need to call Monaco for that info. He said in most cases the Navistar Engine Brake is typically used, this is an internal brake worked off the exhaust valves, kind of like a Jake Brake, but not. i then called Allied Rec Group (monaco) in Colburg, they said according to the moho build sheet it says i have a "turbo exhaust brake" - never heard of that before, we concluded whoever typed the build sheet my have misused the term Exhaust Brake. all this said, the HR owners manual reads nothing of an exhaust brake. so darn confused. asked all the folks i talked to if they are getting any similar complaints, none before me. i also have a tow brake system in my jeep GC tow car, have this cranked to the max and still having hard time controlling speed down grades. Anyone else having issues or suggestions would be helpful? thanks

If I remember correctly, the Endeavor/Diplomat I saw with the MF10 engine, there was a 3 position switch on the smart wheel for the engine brake. This was at the Tampa Super Show and Brett Howard was there's with Alliance Coach. I specifically asked him about this brake and he assured me that this was an internal engine brake. Low was transmission downshift only. Mid position was 3 cylinders and high was all 6 cylinders. There is also an on/off switch somewhere. Does the transmission select 2nd or 3rd automatically?

There is a member who use to post regularly, Trap90, who has your same coach in the Diplomat version. You could try to PM him for info about the brake.

Steve Ownby
Full time since '07

Traps90 · 11-21-2014, 02:35 PM

We have the same coach, and it definitely has an engine brake that works exactly like Steve just said. When we have it on the 3 or highest setting it will slow the coach down on a 5% grade and will hold it own on a 6% grade, this is at 55-60mph. I almost always have the engine brake turned on and do not manually touch the tranny. We just let the computer do it's thing (the computer is way smarter than I am in this case).

The engine brake on your coach should work better than on your older coach.

I'm suspecting that yours is only working on Stage 1, cause the engine brake on ours works great.

Dennis_K · 11-22-2014, 10:04 AM

Read your Owners Manual about the engine brake. Mine is a three stage unit and the manual states:

Setting "Hi" utilizes all six cylinders. The
"Med" setting uses four cylinders while "Lo"
utilizes two cylinders. The engine brake will
activate when the throttle is released to the idle
position. Press Off to cancel the engine brake.

Even on "Hi" mine doesn't always keep the speed under 65 on a 5%+ grade. Over 65 it's seems to be useless. The maximum holding power is at about 2200 rpm, if you exceed that you need to get on the brakes. There have been times I will need to slow down enough to shift to a lower gear in order for the engine brake to hold.

When I know a downhill is coming I slow down to at least 60 before the crest of the hill, at the crest I make sure the system is on Medium and the cruse control is off. Once you are off the throttle the engine brake will come on and the transmission will downshift. From that point I can switch the to Hi or Low depending on what's needed.

Here is a video of how the MaxxForce engine brake system works.

https://www.youtube.com/watch?v=Ae_D2Coot34

ctundra · 11-22-2014, 10:27 PM

thanks for the information. i have checked my owners manual it states Engine Brake (EB), two stage' Low for less braking and Med/High, which are the same, for more braking. i have followed the instructions to apply the EB but does not seem to be working. My older Moho had a PAC Exhaust brake and when activated you could hear it working - with the EB system on my MF10 i can't hear any difference when i turn it on - only hearing the road noise as i whiz down a grade at brake-neck speeds! very darn aggravating and scary at times...

Larry and Suzette · 11-23-2014, 09:09 AM

I too have a 2013 endeavor and have had no issues with the engine brake. I always make sure the cruise control is off, not canceled but OFF, and press the 2 or 3 on the smart wheel switch.

ctundra · 11-23-2014, 08:13 PM

thanks for the comment. i rarely use cruise control and press 2 or 3 on the steering wheel when trying to engage the EB.

Larry and Suzette · 11-23-2014, 10:39 PM

Quote:

Originally Posted by ctundra

thanks for the comment. i rarely use cruise control and press 2 or 3 on the steering wheel when trying to engage the EB.

I wonder if there is an issue with the smart wheel controller that would not send a signal to the exhaust brake?

Larry and Suzette · 12-08-2014, 09:10 PM

Quote:

Originally Posted by Larry and Suzette

I wonder if there is an issue with the smart wheel controller that would not send a signal to the exhaust brake?

I have been looking at pg 193 in my owners manual and I see a relay, "Exhaust brk sol" and a related fuse F84, if I am reading the diagram correctly.

Perhaps a failure in the relay or a blown fuse could be the problem.

ctundra I'm interested in your problem because one day it could be my problem. So if you have an update please let us know.

Larry K

ctundra · 12-09-2014, 05:39 PM

Larry, yeah I saw the same and checked. both are okay. last week we drove from northern Arizona to Tucson - actuated the engine brake several times to see if it would come on, still nothing happened. another interesting thing happened the last 50 miles of the trip, dash gauges started malfunctioning - gauges would max-out for a second then return to normal - then would bottom out and return to normal. none of this caused the engine to shutdown. will be taking it into the shop after first of the year - will follow up on this post when I find out what the problem is. thanks.