# allison tranny question



## 04PaceArrow (Sep 2, 2013)

Hello All,

We have a 04 Fleetwood Pace Arrow on Workhorse Chassis.
GM gas motor with Allison trans.
This is a new to us coach and our first with this trans.

My question:
During travel on highway approx every 2 minutes a loud revving sound would start, as if the motor was racing but the rpms did not change,
the sound would last for about 20-45 seconds then fade off.  This happened constantly on the trip.  
We were running 65-70mph, air temp in high 80s to low 90s.  Did not notice any change in power or speed of the rig during the times of the noise.
It sounds like the motor racing then fades to off.  It starts slow, builds then back off for about 2 minutes, then does it again.

Any info?

All help is appreciated.


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## LEN (Sep 2, 2013)

With no RPM or speed change with the moderate to high temp out I would guess, and its only that, it's your fan for cooling pulling more air through the radiator.

LEM


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## Kirk (Sep 3, 2013)

I make the same conclusion as Len. In fact, I'd bet that the sound comes from the doghouse where the engine is located, rather than from farther back where the transmission is. The fan on gasoline engines of motorhomes has for many years used a clutch to disengage it when no extra cooling is needed. When it does engage, the sound is a roaring sound that does decrease if you lower engine RPM but otherwise continues until the temperature drops, when the clutch releases again.


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## dbarton291 (Sep 5, 2013)

Agree. Sounds like the fan.


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