New 2500 Cummins tow question

[BDAVI]

I have a new (1500 miles) Ram 2500 HD with the Cummins. Yesterday was the first day I pulled a trailer with it. I pull a flatbed (about 2800 lbs) with a Bobcat (about 10200 lbs) on it. I pull in the mountains of Colorado. I started out from a home in Grand Lake that has a steep 600 ft gravel driveway to get to the main road. Because of the loose gravel it takes 4WD to get up the hill. Went up the hill at less than 5 mph and switched back to 2 WD at the main road where I went about 30 mph. I have my instrument cluster set to vehicle info and about 2 miles down the road the transmission temp was at 188 deg. By about 3 more miles down the road the temp was back at 168 deg (which is where it is most of the time). I pulled the load across the continental divide and Berthoud Pass at about 45 mph up the steep pass road and the temp stayed between 168 - 170 for the entire rest of the trip down to Denver. My previous truck was a 96 Dodge Ram with the Cummins (25 years old and 260,000 miles and still going STRONG) but because it didn’t have a way to see the transmission I don’t know what was “normal” pulling the same load in the same situation.

Any ideas?
Is this normal?
Did the 4 WD have something to do with it?
At what temp should I be concerned with the transmission temp?

Thanks for any help...

 

[MADDOG]

Your temps were in the safe range. My 2017 temps were 170 - 171 at freeway speed in moderate to warm weather when not towing. It pretty much stayed there when I was towing and would creep up to 185 - 190 pulling 12K up 6% grades.

 

[BDAVI]

Thx Maddog!

 

[BDAVI]

Maddog... any idea why the temp went up to 188 deg so fast in the first part and then dropped back to 168-170 for the remainder?
Thx

 

[dhay13]

Likely because you were at slow speeds so no airflow through your cooler

 

[BDAVI]

Thx

 

[runamuck]

I was in the grand lake area last week. pretty nice there

 

[JayLeonard]

Likely because you were at slow speeds so no airflow through your cooler

That makes sense to me and you could have been at really low engine rpm so not much fan help at that point.