Allison 3000 mh limits speed when trans oil less than 120F

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pieczko123

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Jul 27, 2018
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Has anyone experienced limited speed from an Allison 3000MH when starting from cold temps - OK, cool temps?

Example - unless I allow the tranny to warm up to around 120F all I can get is about 45mph.  Stop for the night at a roadside RV park, leave in the morning with air temps in 30s, immediately get on ramp to interstate and bogged down at 45mph.  No engine codes or tranny codes, no warning lights.  This isn't an issue in normal temps as by the time I get slides in, jacks, up and toad hooked up it's warm enough I don't experience it - only when in the 30s or less.  Previous owner never winterized and kept her in warm climates, so no idea if this is a new or old thing, but for the last 2 yrs I've experienced it.

The tranny manual and Allison tech support say this should not occur.  According to the tranny manual the only time the tranny limits speed due to cold operation is if the sump temperature is less than 19F and then it limits the gears to N, R, and 2nd gear until above 19F.

I suppose the temperature sensor could be out of calibration?

Anyone else experienced this?

2012 Itasca Meridian, 40U, Freightliner Chassis, Cummins ISC 8.3, Allison 3000MH
 

pieczko123

New member
Joined
Jul 27, 2018
Posts
3
Also, when talking to local Allison service, they said to pull up diagnostic codes - did that and nothing, and since these don't clear out there haven't been any. 
 

pieczko123

New member
Joined
Jul 27, 2018
Posts
3
It occurred the first year I owned it (4yrs on RV) prior to changing the oil and filters. 
I mentioned it to the service techs at the fluid power shop where I bought the filters and they mentioned they put the tranny in first with brakes on and in 3 min its up to op temp, and checks your brake holding.
Changed the oil and filters and same thing.
 
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