HelloI have a 1996 Monaco Dynasty. I am currently at a RV camp 3 hours from home to see fall colors. While driving at first the RV was driving just fine. An hour into the trip, I noticed that the RPM was running at 2800 rpm at 5th shift. Got to a red light and when I went to shift from 4th to 5th, the RPM went to 3500 before shifting. So painful. It got to the point where I kept the speed to under 80 km so that the RPM would stay around 2800. No changes to any of the gauges while the strong increases in RPM. No changes in sound of engine when driving with high RPM. Last week the RV was in the shop when the fuel solenoid was replaced, line from oil to turbo boost replaced, cooler and fuel filters changed, and turbo boost was repaired as it was not working. I will be going home Wednesday and would really appreciate any thoughts. Thank you in advance.

Ever bother to change the fluid?

Which fluid(s) were you thinking of and how would that impact the issue?

Tranamiasion fluid of course. Trans fluid can make a hugh impact on how the trans works. Mainly slippage of the clutches. Which if you allow it to go on for very long could result in a very very expensive rebuild.

Use the Allison shift pad to check for diagnostic codes.If you need instructions on doing it, let us know.Let us know what you find.

Will be out running errands, so here is the "how to":Ignition on, engine offPush up and down arrows on the Allison shift pad at the same time. Your transmission was right at the time that added "check fluid level from the shift pad), so you will either see O L or d-1. If O L, hit the up and down arrows again at the same time to get to diagnostic codes (d 1).If there is a diagnostic code stored, it will flash d 1 and then the two digit codes. Copy it down. If no codes, it will show d 1 - -. If you get a diagnostic code, push the mode button to go to the next diagnostic code. when you get a - -. you are finished. Just turn off the ignition.Allison's website and the Allison owners manuals that come with your coach will have the list of codes.

RPM rises to 3500 to shift from 4th to 5th | Good Sam Community

ricelake922
Explorer
Oct 09, 2018
I got - -. No codes
wolfe10
Explorer
Oct 09, 2018
d 1 - - means no codes.

What engine-- that RPM would have most diesels spitting parts out (IF really that RPM rather than a tach issue).

Were speed and gear indicated what you normally see for that speed? Power OK?
ricelake922
Explorer
Oct 09, 2018
All other instruments were just fine. A friend at a RV shop in FL told her that you can’t blow the engine as the governor in the fuel pump will not allow the engine to blow. So now it appears that it is the tachometer and could be the sensor which is a line attached to the alternator. I was told by freightliner that most new RV do not have a tach but people rely on the other instruments for issues. I am going to ignore the tach, crawl home, put the RV into storage for the season and deal with it when the RV comes out in the spring. There is always something but having fun learning.
11178adm
Explorer
Oct 10, 2018
regardless if this is a 3126 Cat or a 8.3 Cummins it would have had a cast iron hemorrhage by the time it got to 3500 rpm. as stated in other posts the most likely cause is a tachometer issue
oldave
Explorer
Oct 10, 2018
I'm almost certain it's the tach .
The mechanical engines, those not computer controled like
I'm thinking yours is used the alternator pulses as a
signal for the tach .
The tach acting up is often a sign you may have alternator trouble .
You might want to get it checked out before putting it in storage .

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RPM rises to 3500 to shift from 4th to 5th

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