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kernst52 · 06-12-2018, 12:20 PM

I have a 2007, 35-foot motorhome with an Allison 1000 tranny, 30,000 miles total and 12,000 miles since the last fluid change using synthetic. I have this noise that lingers after the tranny shifts back up to 6th (or maybe it is called overdrive) after being in 4th or 5th climbing an upgrade of just about any size. It sounds as if the rig is running in 4th gear - that is the king of noise it is and it lingers after the shift up to 6th for quite a while now. Maybe a minute or 2. the time is getting longer the last 2 days or so. It is shifting properly and at appropriate times. I watch to tach closely and the noise will eventually shut off like a valve or switch is changes. Oddly, the sound is really a lot like it is running in a lower gear but I am sure it has shift up to 6th.

We are in Kansas City visiting relatives now and a long way from home. Any ideas what that noise could be? I am worried.

Thanks,

Ken

Skip426 · 06-12-2018, 03:27 PM

It’s not just the rad cooling fan cycling is it?

CJ7365 · 06-12-2018, 03:43 PM

A short recording of the noise might be more helpful in determining what it is.

WinnieView · 06-12-2018, 04:15 PM

Quote:

Originally Posted by kernst52

I have a 2007, 35-foot motorhome with an Allison 1000 tranny, 30,000 miles total and 12,000 miles since the last fluid change using synthetic. I have this noise that lingers after the tranny shifts back up to 6th (or maybe it is called overdrive) after being in 4th or 5th climbing an upgrade of just about any size. It sounds as if the rig is running in 4th gear - that is the king of noise it is and it lingers after the shift up to 6th for quite a while now. Maybe a minute or 2. the time is getting longer the last 2 days or so. It is shifting properly and at appropriate times. I watch to tach closely and the noise will eventually shut off like a valve or switch is changes. Oddly, the sound is really a lot like it is running in a lower gear but I am sure it has shift up to 6th.

We are in Kansas City visiting relatives now and a long way from home. Any ideas what that noise could be? I am worried.

Thanks,

Ken

Take a look at these similar previous posts;

https://www.google.com/search?q=Alli...earch=irv2.com

kernst52 · 06-13-2018, 12:11 PM

OMG, you might be right. It is lingering longer in hotter weather here in KC. I will check previous posts for Allison 1000 noises. Also, maybe the radiator cooling fan noise is changing, which would make me notice it lately.

Thanks.

Arch Hoagland · 06-13-2018, 10:03 PM

I'd really suspect it is the fan on the engine engaging as the engine heats up to around 200 degrees.

It normally comes on and runs about a minute or two and then quiets down.

Although I'm surprised you haven't heard it before living in Tehachapi, CA. It's a pretty steep climb into your area especially coming out of Bakersfield.

If you get home and still think you have a transmission problem the Allison dealer in Fresno is excellent and honest.