Question for you Class A Diesel Pusher Folks

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emmaus road

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I just purchased a 2003 Holiday Rambler Endeavor 40 foot 3 slide model with the Cummins 330 Diesel pusher.  While I'm driving, she shifts like a dream, however, when I'm going up hill, and the turbo kicks in, she gets sluggish and jumps from time to time.  Almost like a hesitation.  Is this normal at all or should I even feel anything when the turbo kicks in. 
I've always owned a class c Ford so now I get to learn all the ins and outs of the diesel pusher.  I tell you though, I sure am enjoying the bigger tires and quieter ride. 

Thanks for all your advice and help.
 

AStravelers

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Assuming you have the Allison transmission, what does the shift indicator show when you have the problems?  There should be 2 numbers, the number that was requested and the gear the transmission is actually in. 

If the gear the transmission is actually in doesn't jump you may have a fuel starvation problem.  Could be a clogged fuel filter.  OR.... the fuel lift pump could be clogged.

I had a 2003 Phaeton with the Freightliner chassis and Cummins 330, and the lift pump got clogged. Just trying to go over a highway overpass the engine would bog down.  I had to replace the rubber fuel lines from the lift pump to the metal tubing coming from the fuel tank and add an additional filter before the lift pump. 
 

Gizmo100

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Welcome to the RV Forum emmaus road

And Congrats on the new toy
 

Gary RV_Wizard

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As Dan says, that's not the turbo "kicking in" - it is variable speed and always on.

Diesels are highly sensitive to both fuel and air flow and the most common reason for sluggish performance or hesitation is a dirty fuel filter, followed by a dirty air cleaner. Since this coach is new to you, I suggest changing both to get a fresh start.

A clogged inlet screen on the fuel lift pump is another possibility, but don't fret about that until you try to simpler stuff.
 

emmaus road

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AStravelers said:
Assuming you have the Allison transmission, what does the shift indicator show when you have the problems?  There should be 2 numbers, the number that was requested and the gear the transmission is actually in. 

If the gear the transmission is actually in doesn't jump you may have a fuel starvation problem.  Could be a clogged fuel filter.  OR.... the fuel lift pump could be clogged.

I had a 2003 Phaeton with the Freightliner chassis and Cummins 330, and the lift pump got clogged. Just trying to go over a highway overpass the engine would bog down.  I had to replace the rubber fuel lines from the lift pump to the metal tubing coming from the fuel tank and add an additional filter before the lift pump.


ok, my reader says 6 all the time.  That's either a 6 or a G for go lol.  But it doesn't change as the gears shift. 
It only does it going uphill when you can see the turbo gauge going up.  I kinda was thinking it was a fuel or an air intake or something.  But remind you I am no mechanic, but learning little things as I go.
 

emmaus road

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Utclmjmpr said:
You should not feel the turbo "kick in",, it's "kicked in" anytime the engine is running.>>>Dan


Thanks I guess what I meant by kicking in was when the turbo gauge moved way up when I accelerate up hills.  Still learning the language lol
 

emmaus road

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Gary RV_Wizard said:
As Dan says, that's not the turbo "kicking in" - it is variable speed and always on.

Diesels are highly sensitive to both fuel and air flow and the most common reason for sluggish performance or hesitation is a dirty fuel filter, followed by a dirty air cleaner. Since this coach is new to you, I suggest changing both to get a fresh start.

A clogged inlet screen on the fuel lift pump is another possibility, but don't fret about that until you try to simpler stuff.

Thanks for the advice.  I was actually gonna have it serviced so I could have a good record seeing as how we use if for a music group and travel nearly every weekend. I didn't feel it should be normal.  I drive a tractor trailer and I've never had that, except when my fuel filter needed changed. 
 

Larry N.

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emmaus road said:
ok, my reader says 6 all the time.  That's either a 6 or a G for go lol.  But it doesn't change as the gears shift. 
It only does it going uphill when you can see the turbo gauge going up.  I kinda was thinking it was a fuel or an air intake or something.  But remind you I am no mechanic, but learning little things as I go.
So you only have a single digit readout for which gear? And it stays 6 all the time? Then that's probably the selected gear (like D or R or N on a car transmission), rather than the gear it's actually in. So many Allisons actually have two digits there, the left one being gear selected and the right one being the gear that the transmission is actually in (via auto shifting).
 

emmaus road

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Larry N. said:
So you only have a single digit readout for which gear? And it stays 6 all the time? Then that's probably the selected gear (like D or R or N on a car transmission), rather than the gear it's actually in. So many Allisons actually have two digits there, the left one being gear selected and the right one being the gear that the transmission is actually in (via auto shifting).

I'll take a picture tomorrow and show you what I mean.
 

Gary RV_Wizard

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ok, my reader says 6 all the time.
Yeah, that's the selected or "target" gear.  Originally Allisons had two gear windows, then for a dozen years Allison shifters displayed only one, but recently they went back to two windows again.
 

ArdraF

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We have a 2003 Monaco Executive and just had the turbo boost and air cleaner replaced.  We noticed on our last trip that it was sluggish.  There's a piece of rubber in the turbo boost that had disintegrated and we only had 5 percent "boost" when it was checked.  What a difference there is now!  It's more like when it was new.  Good hill climbing and good start up from a stop light.

ArdraF
 

heatinh man

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it sounds like you have the same shift selector I have.  Mine has One digit that tells you the highest gear the transmission can go into.  If you are in the mountains you can use the arrow keys to set the transmission so it can not go into a higher gear and shift back and forth.  I a lot of times will set it 5th gear as the highest it can go into.  My coach is a 2004
 

8Muddypaws

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If you?re going up hill try to keep your RPMs in the sweet spot.  On mine it?s 1700-2000 RPM, yours will be different.  I don?t wait for the engine to bog down and the transmission to shift on it's own. When it gets down to about 1500 I manually shift down a gear.  Those shifts can cause quite a lurch.

Decelerating with the retarder on makes even bigger lurches.  It?s done this since the day we got it and has suffered no ill effect.  So far the only part to fail in my transmission was the rear seal.  That was easy to replace.

 

emmaus road

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heatinh man said:
it sounds like you have the same shift selector I have.  Mine has One digit that tells you the highest gear the transmission can go into.  If you are in the mountains you can use the arrow keys to set the transmission so it can not go into a higher gear and shift back and forth.  I a lot of times will set it 5th gear as the highest it can go into.  My coach is a 2004

Yes your right. That?s how mine operates.
 

Gary RV_Wizard

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Not disagreeing about maintaining the RPM "sweet spot", but I've not seen an Allison 3000 or 4000 that did not keep RPMs in the "sweet spot" at all times. Nor fail to change gears quickly on its own to avoid "bog down".  The controls of an Allison coupled with a Cummins or Cat electronic engine are near-marvelous. Manual shifts are all but obsolete.
 

jor_az

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can use the arrow keys to set the transmission so it can not go into a higher gear and shift back and forth.

I wonder if the jumping you are describing is just the transmission constantly hunting for the correct gear. I have found that putting the transmission selector in the "mode" position makes for a better mountain driving experience. Mode changes the shift points. I like to anticipate the appropriate shift point myself but I have found with my current rig 8.3 Cummins with 3060 that the mode selection is pretty darn close to where I would shift anyhow. I would suggest you give mode a try, let the transmission do the shifting and see if that addresses your issue. Just push the mode button on the selector at any time. Good luck.
jor
 

8Muddypaws

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On every Allison I?ve seen the ?Mode? causes it to shift into the next higher gear sooner and stay in the higher gear longer when slowing down.  Exactly what you don?t want in mountains.  According to the manual it can be programmed the opposite way but I have never seen one.  Not that I?ve looked at hundreds of them or anything.
 
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