Engine & Trans Temp

[Mr. Jon]

I was towing my mini excavator yesterday (machine & trailer = 15,000 lbs.) and engine temp went over 210, almost to the next line which would be about 235, which has never happened before, and trans temp reached 205, which never got above 190 before. I have a 2007 Sierra NBS 3500HD DMAX Allison ext cab 8' bed completely stock except for the Reese Titan 18,000 lb hitch. Outside temp was about 80-85 degrees and I was going up a long steep hill. Both temps lowered quickly after I crested the hill. Is this something to worry about or are these temps normal? If these temps are too high, are there any suggestions to help lower temps?

[96chevy7.4L]

Well the engine temp is a lil high. The trans temp is the temp to worry about. I would put a bigger transmission cooler on it. Look at a B&M Super cooler. The factory cooler is marginal at best. And the weight your towing the transmission needs all the help you can give it. Might even look into a higher capacity transmission pan as well. Spend a lil now or a lot later.

[markw8]

Trans temp is normal for the conditions. Engine could see that pulling 15000 on a longer hill at 85 deg. Probably normal too.

 

Mark

[masterp2]

Normal for a duramax, and not an issue unless the fan did not come on at some point. I am guessing it did. That should have reduced engine temp.

 

Hi elevation will make this worse, fwiw.

[Mr. Jon]

Thanks for the replies. I'm thinking about a larger pan and Transynd fluid. I can't find a Derale that fits the Allison, do they make one that fits? I found Mag-Hytec, it's over $300 with the filter and shipping. If I change to Transynd, do I need to do a complete flush? I have Dexron VI in there now.

[Zembonez]

You need to also consider that the gauges are just "reasonably close" to actual temperatures and not exact. If the temp came back down once it was not having to work so hard, it appears that the cooling system was up to the task.

[dewfpo]

If I change to Transynd, do I need to do a complete flush? I have Dexron VI in there now.

 

Allison you can do 2 pan drains and you should be good to go if using Transynd. A complete flush gets more of the old out and more new in. 2 pan drains get about 85% out.

 

DEWFPO

[JoJoJim]

I have a friend who has a Duramax with similar miles and did the same temperature thing. He changed the water pump just to see if anything was going on and the impeller blades were really worn. Cooling fluid still looked real good. Anyway temperature has since stayed down at the 190 degree level.