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WYDan · 02-06-2022, 11:22 AM

I have a 2008 Damon Astoria 3776, owned since new and now has 70,000 miles. It has been a very good RV for us with very few problems. I have an issue that cropped up a couple of summers ago and I, and others, have been trying to diagnose.
The issue is that it starts to overheat on a long slow climb. Almost as if it does not shift down enough and overworks the engine as the heat climbs.
These are long gradual climbs that I never had to take off cruise control before and now I have to or I overheat..

What we have done:
Flushed radiator
cleaned front of radiator (Yes it was very thick) - The cleaning helped.

We are beginning to THINK torque converter.

Any thoughts before I just have the torque converter replaced?

Cummins 340
Allison Transmission

Thanks for sharing any ideas!

wolfe10 · 02-06-2022, 11:34 AM

Did you clean the cooling package from the FRONT? The front of the CAC is where most of the dirt will be deposited.

And, YOU, not the Allison can choose a gear where you will not overheat. Basically toward the top end of the engine RPM range at less than WOT (Wide Open Throttle).

WYDan · 02-06-2022, 11:53 AM

Quote:

Originally Posted by wolfe10

Did you clean the cooling package from the FRONT? The front of the CAC is where most of the dirt will be deposited.

And, YOU, not the Allison can choose a gear where you will not overheat. Basically toward the top end of the engine RPM range at less than WOT (Wide Open Throttle).

Thanks wolfe. Yes, we have cleaned the front of the CAC and it was caked. The cleaning did help, but not take care of the issue.
The more I research, the more I am now thinking it could be the fan clutch issue on the 340's. Freightliner Service Solution 3737

wolfe10 · 02-06-2022, 11:54 AM

Yes, if you have a Freightliner with clutched fan, that HAS been problematic.

Braggs · 08-03-2022, 02:24 PM

I too was having overheating issues on my 2008 Damon Astoria 3776. Since the fan clutch was suspect, I pulled the fan clutch fuse and haven't had any overheating problems since. The fuse was located in the rear driver compartment (shore power cord). It doesn't fix the fan clutch but it does cause it to lockup and turn with the engine permanently.