Good Sam Club Open Roads Forum: Class A Motorhomes: Allison 2500 downshift issue
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 > Allison 2500 downshift issue

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distal703

Prescott

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Joined: 11/01/2019

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Posted: 11/01/19 03:31pm Link  |  Quote  |  Print  |  Notify Moderator

I have a 2014 Itasca Meridian 34B with a 2500 Allison 6-speed trans. Lately when I am in cruise control it does not downshift as needed. Especially from 6 to 5. When in 5th it downshifts when needed part of the time. Some times when I first start out in the morning it shifts fine, but when I stop for a break it stops downshifting properly. It works fine in non-cruise control mode. I'm thinking it's a sensor, but which one and is it a DIY item?

* This post was edited 11/01/19 05:49pm by distal703 *

SidecarFlip

SE Michigan

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Posted: 11/01/19 05:54pm Link  |  Quote  |  Print  |  Notify Moderator

Basically nothing on an Allison is DIY except fluid and filter changes and even that requires specific fluid and filters. Take it to an Allison repair facility and let them diagnose the exact issue and repair it accordingly. Allison.s are very touchy about fluid change intervals too. Are you doing that?


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wolfe10

Texas

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Posted: 11/01/19 06:50pm Link  |  Quote  |  Print  |  Notify Moderator

Not familiar with the 2500.

But, on all their larger transmissions you can check for DIAGNOSTIC CODES from this shift pad.

See if this feature is available for your 2500.


Brett Wolfe
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Ex: 1997 Safari 35'
Ex: 1993 Foretravel U240


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jplante4

Cape Cod

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Posted: 11/02/19 07:42am Link  |  Quote  |  Print  |  Notify Moderator

Does the 2500 have a mode button? On the 3000, if that is pressed it delays the downshift (kind of like Eco mode) to prevent constant downshifting on gentle hills. The display should say Mode On or something like that. It's possible that the ECM has been programmed to turn that on with the cruise control.


Jerry & Jeanne
1996 Safari Sahara 3530 - 'White Tiger'
CAT 3126/Allison 6 speed/Magnum Chassis
2014 Equinox AWD / Blue Ox


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