Monaco Knight 2000 won't go over 40mph w/Cummins & Allison 1000, Morse shifter

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FoxKat

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Dec 22, 2016
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Okay ladies and gentlemen, I need help, because I can't find technicians that can diagnose this. This Monaco runs beautiful, the engine purrs like a kitten, and it revs up quickly when it's in park like it's got more power than it needs. Once I drop it into drive, it barely crawls out of a parking place, the engine doesn't even sound like it's struggling, it just doesn't rev up at all, and the coach struggles to even get up to local street speeds, let alone highway speeds. It feels like when I would compare my car if I shifted into second gear and tried to start from a traffic light in second gear, because to gear ratio is too high and the torque required to move the vehicle is higher than the engine can muster. On the other hand, in second gear it also seems too make sense that it wouldn't be able to go above 40 miles an hour, because that could possibly be the maximum range of that gear ratio.  When on the highway, with the pedal to the floor, 40 miles an hour is the maximum speed, unless I get the help of a gentle Hill where I might make it to as much as 44. This is with the engine revving steady at approximately 2,200 RPM.  Some people have told me that 2,200 RPM in this type of rig is a high RPM, but I've read that these Cummins engines can rev to as much as 3,500 RPM without doing any damage, so I find it strange that I'm being warned about running at 2,200.p

The technician's first suspicion was that the engine was being starved for fuel and so they replaced both fuel filters, and their in bay testing while in park, and with no load applied lead them to believe that the engine would run beautifully.  Unfortunately, the engine does run beautifully both at idle and when the accelerator is pressed down while in park or neutral, but that's the only time.  Other symptoms, are that no matter what position I put the gear shifter in, first, second, drive or overdrive, I feel and hear no difference in either the torque, or the speed of the vehicle, and detect no shifting whatsoever, either while at a full stop, or at any speed up to and including 44mph.  Also, don't know if this will be related or not but the speedometer is pegged at 0mph, and does not move off that position no matter how fast I go.  Also, the odometer and trip meter are not counting miles.

When trying to accelerate from a dead stop, it doesn't even sound like the motor is trying to accelerate, it just pretty much sounds like a more aggressive hum then when it is idling, and the RPM just increases slowly

I took it first to a local minor repair, lube and filter shop where they replaced the fuel filters.  Next I took it to an Allison transmission shop, but in their attempt to connect the computer to the RV, they couldn't find a port that would recognize the transmission. The only Port they could locate was to the top right of the radiators in the rear, and it's labeled engine. I understand there might be another Port somewhere on the rig, one technician said he's seen them sometimes on the frame rails underneath, but couldn't be sure if this vehicle had one there or not since they never crawled under.

Allison seems to think it's a motor problem, and a trying to say that the motor is losing power. They've said that if the motor didn't have enough torque, it would never let the transmission shift because the transmission will be looking at the motor's RPM and waiting for it to reach a certain number before it would let it move to the next gear.

It's sitting in the Allison's service center parking lot, and I hope to get it looked at again starting on Monday.

Diagonally across the street from Allison is Cummins, and I've spoken with them but they seem to think that the problem is not related to the motor, and they're pointing to either the transmission, or to the chassis as where to troubleshoot.  Regarding the chassis, I'm not sure I understand that philosophy, other than perhaps that whoever makes the chassis is responsible for the linkage to the transmission and possibly that's what they're thinking?

Since this is a Freightliner chassis, I called them and described the problem.  They're trying to Convince me that this is a transmission problem.

I'm wondering if it can't be that Morse control shifter which is being used as a mechanical control for the electronically-controlled Allison transmission. I've been told that that mechanical shifter would have to go to an actuator motor, which would then convert the mechanical action into the electronic actions of contacts closure that would tell the ECT what gear to put the transmission in.  Could it be a fuse for that actuator motor?

Again gentlemen and ladies, I'm a novice so I'm only going on my limited amount of knowledge on a variety of subjects being a geek who likes to research and read and learn. I know a little bit about a lot of things but nothing at all about these rigs. 

Monaco themselves told me they couldn't help me because they aren't the same Monaco that built this rig in 2000. So I'm stuck between four different rocks and hard places. Monaco, Allison, Cummins, and Freightliner all not knowing what to do.

I have spoken to Freightliner and they suggested I bring it in, but they also pointed to Allison since they believe this is a shifting issue.

Could this manual shifter be replaced by the standard button shifters that are on most Allison transmission vehicles that I've seen?  Why would anyone have put a Morse Control shifter in and then "jerry-rigged" it with an actuator motor just to get to electronic control? Seems like the only purpose would be to create more failure points in my humble opinion.

Hopefully someone out there can help me make some sense of this, but more importantly help me get it actually correctly diagnosed and repaired as it is my only home at the moment. My house burned down and my family of three, my wife, son and I are technically homeless oh, and bought this rigged so that we can both travel and work in our positions as traveling sales people. Don't feel sorry for us, because our jobs, my wife's and mine are both very good jobs that pay very well, but we had very little money to start with after a long period of being jobless after the fire so we bought this used rig so that we can avoid paying the hotel expenses that we have to cover at each location where we work for two weeks at a time.
 

Robert K

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Jan 30, 2011
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652
What motor what transmision model. @2200 rpm in 6th gear I would be up to 70 going down the road. Sounds like transmission
 

Old_Crow

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Have you mentioned the inop speedometer and odometer to the techs?  I know on a gas rig, if the computer isn't getting a signal from the speed sensor that the trans won't work properly.
 

FoxKat

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HueyPilotVN said:
Have they checked the air cleaner?

No, but I appreciate the recommendation and will have it checked first thing on Monday.
 

FoxKat

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Dec 22, 2016
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Old_Crow said:
Have you mentioned the inop speedometer and odometer to the techs?  I know on a gas rig, if the computer isn't getting a signal from the speed sensor that the trans won't work properly.

That makes complete sense, considering the transmission is electronically controlled. I did mention it, but they did not seem to have the same assessment. I will reiterate and include your information on Monday morning. Thank you very much for the suggestion.

I have only one curious question regarding that.  If the speed sensor tells the transmission what gear to be in, why would it start out in such a high gear? Seems to me, if the speed sensor was showing zero, the transmission would want to be in first gear.  Just a thought.
 

Robert K

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I think your transmission is not upshifting and your engine is not revving beyond that to protect itself.
at least I think that is what my old Cat would do
 

Gizmo100

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FoxKat said:
That makes complete sense, considering the transmission is electronically controlled. I did mention it, but they did not seem to have the same assessment. I will reiterate and include your information on Monday morning. Thank you very much for the suggestion.

I have only one curious question regarding that.  If the speed sensor tells the transmission what gear to be in, why would it start out in such a high gear? Seems to me, if the speed sensor was showing zero, the transmission would want to be in first gear.  Just a thought.

Warning I know nothing about any part of your rig.....It's all way above my pay grade.

That said,
It sounds to me that your system is going into a limp mode to protect itself due to faulty codes. The fact that the speedometer is pegged at 0mph, and does not move off that position no matter how fast I go.  Also, the odometer and trip meter are not counting miles. would suggest that your system is not getting information and so defaults to limp it to the shop.

 

Ken & Sheila

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You should have a diagnostic plug on the firewall to the left of the steering column. If not there then look int the front "run" compartment - outside compartment in front of the front wheel on the drivers side.


This plug should access both the engine and the transmission.


ken
 

Cooperhawk

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I have had the same symptoms when my fuel gelled.  The engine ran fine but when I put it in gear it could not get enough fuel to produce power.  Not suggesting you're gelled, or are you, but it does sound like fuel starvation.  Maybe a pinched line or something similar.

We had a problem with ours last Fall but it was due to a leak in the trans oil cooler lines.  It would rev, but would keep shifting down til we were only going about 30mph.  Add trans fluid and away we went til it leaked out again.  Yours sounds different.
 

cvsteed

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Jun 2, 2012
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Most RV diesels don?t use the standard type OBD2 connector.. Instead you need something like this for your RV so you can read, diagnose, and even clear the fault codes...

https://www.scangauge.com/shop/scangauge-d/

It sounds like your RV Allison is in ?limp mode? which means it will only operate forward 8n 2nd gear regardless of where you place shifter..

Hope the link helps....a good RV motorhome repair shop would know where to hook up engine code reader to

 

kdbgoat

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I'm certainly not an Allison  tech, but from the issues I've read about here, and the fix for a lot of those issues was just a matter of following the wiring and cleaning up all the connectors. Doing that seems to fix a lot of Allison woes. And to me, it does seem like a transmission issue, not an engine issue. I think cvsteed hit the nail on the head with the trans being in limp mode.
 

IBTripping

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I don't know much about diesel engine and transmissions. But, I did have something similar happen on my old 1992 Firebird and the speedometer would not work. I changed all kinds of parts related to the transmission and speedometer. It was driving me crazy until I finally replaced a $10 temperature sensor which solved the problem. I still don't know the relationship of that sensor to the symptoms with my speedometer. Based on that experience, I'd guess a wire or sensor or something cheap and simple is causing your problems. Unfortunately, your mechanics haven't seen a problem like your MH has. Thus, it will probably take a lot of time along with continued trial and error before they resolve it. Best wishes on their finding and fixing SOON!!!
 

Robert K

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When my throttle position senser under the pedal went bad The transmision was not affected.Mine is a MD3060 are you sure yours is a 1000 series.When I did have a do not shift light come on intermitantly it was a couple old corroded butt connectors I found. Never a limp mode I don't think.
Do you have Turbo Pressure built up at 2200 RPMs.
 

ArdraF

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Feb 12, 2006
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I'm not going to try to diagnose your problem, although it does sound like a lack of fuel problem.  We have a 2003 Monaco Executive, Cummins/Allison combination.  It's the same "vintage" as yours.  For most of its line (including our 1999 Windsor) Monaco built its own monocoque chassis which it named Roadmaster (not related to Roadmaster towing products).  That being the case, any chassis questions need to be answered by a Monaco person, not the new Rev Group.  If you're near Coburg, Oregon (where Monaco was located) many former Monaco employees have started their own companies.  One of these is Source Engineering.  The owners, Scott and Jim, know the Monaco transmission and chassis parts quite well because they were designers and testers.  I recommend contacting Source Engineering, Inc. at 541-343-0293 or 610 Commercial Street, Eugene, OR 97402.  If they can't help you, perhaps they can steer you to someone who can help.  Also as background, the Magnum chassis was used in Beaver and Safari motorhomes.  I'm not sure what they used with the Freightliner but Scott and/or Jim should know.

ArdraF
 

Arch Hoagland

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Did it ever work correctly or was it like this when you bought it? 

Were you in the California fires? 

Where are you located?  if near Fresno California I can recommend some good shops.
 

Gary RV_Wizard

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Since this is a Freightliner chassis, I called them and described the problem.
I just caught this and am confused.  Yours is Freightliner?  I've not ever heard of that on a Knight.  The 2000 Monaco Knight is built on the Roadmaster chassis, not Freightliner.  The R4R, as I recall.  Cummins 5.9L engine and Allison 1000MH 5 speed tranny.    Probably doesn't change anything that has been discussed so far, cause the Cummins and the Allison work the same way regardless of the chassis maker.


 

PatStab

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Feb 27, 2016
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A good place to go is in Terre Haute, Indiana, its called Scheid Diesel, they rebuilt my Cummins engine.  I would recommend them.
 

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