Transmission cooler addition and heating

[Larry Fritz]

Our 98 Beaver Patriot 37', Cat 330 has always overheated. Some years ago, we added the blowby extension tube, small CAT pulley, SMC 9 blade fan at Beaver Service center.  Still overheated. Next, at Bend Equipment, we had all the radiator, CAC, etc removed and cleaned with a pressure washer. (But this costs an "arm and a leg" since it takes hours to do)

At the same time, the transmission lines were totally removed from the radiator and a huge external cooler was added on the rear at the upper right side. This seemed great until we started traveling in 85 degree to 100 degree weather and driving continuously several hours. After 2 to 3 hours of continuous driving at under 65 mph, the trans temp (as read on the Silverleaf VSMII dash computer) gradually builds up to 240 degrees or more. At 240 degrees, I stop for 5 to 10 minutes as it cools fairly fast and that is good for another hour or more of travel.

So here is where I would like some ideas from the forum:
1. Would I benefit from reconnecting the trans cooler to the radiator and using both in series for cooling?  (But this puts more load on the engine coolant and coolant temp will increase)
2. Would I benefit from adding a second cooler and mounting it on the side with a fan and running these two coolers in series?
3. Has anyone added more external transmission cooling and how did you do it and how has it worked?

The transmission is the Allison 3060 and it is running Dextron.  I do plan on changing to Transcend which will help some but any thoughts on this situation would be appreciated.

beaverlarry

[Richard And Babs Ames]

We changed to Transynd synthetic fluid and had a 20 degree drop in fluid temperature. Your cooler may be mounted in an area that acts like a heat sink for the engine and if it is of adequate size the addition of an electric cooling fan may help a lot.

[Edward Buker]

Larry,

Your coach transmission seems to heat up when the coach is going slow and the temperature is high. You need to create more airflow through the transmission cooler that you added. If it just relies on passive air flow you should have a bracket built and add an electric cooling fan like what is used on an air conditioning condenser or an automotive radiator. If you have a creative way to bring some cooler air to the heat exchanger with some ducting or venting, perhaps through the side of the coach, that would help optimize the cooling capacity also. If you are marginally acceptable now, it would seem like this type of modification would put you in an acceptable temperature range.

Transynd, as already mentioned, would also serve you better given your marginal cooling issue. I would put a high priority on this change over given it is a small price to pay in order to preserve an expensive transmission. Transynd lubrication qualities hold up at higher temperatures which translates into less transmission wear.

You could consider putting the coolers in series as a last resort if you had some additional radiator cooling capacity that was not needed for the main engine. I think you altered the original configuration to take some heat load away from what was a marginal cooling system. Seems like going back in that direction would be a last resort.
Hope this helps.

Later Ed

[LarryNCarolynShirk]

Larry,
I had the same type 98 Patriot, with the same modifications except the additional cooler.  The change to Transynd helped the most with a 20 degree reduction in the transmission temp and the engine temp.  Try it, you will like it.

Larry