Digging up an old post here - I was looking for something on Tranny temps. I have a 24' v-nosed enclosed car hauler w/10k axles. I used it to move from the east coast (Philly area) to Las Vegas almost 2 years ago (with the 2020 in my signature). I was at max gross, legal on all axles with cat scale slips to prove it, but right at 17,000lbs combined. I watched temps all the way out and oil never exceeded 246. (Only over 240 twice the entire trip, generally down in low 200's). Truck was still new (~1700 miles at start of trip) - still had factory oil, which I changed immediately after arriving in Vegas. Trans temp - I don't remember but it was constantly over 200, probably 230ish. Last weekend we towed the same trailer, much lighter now (~6000 lbs outbound, 4200ish on the return trip) with my brother-in-law's 2020 2500 6.4 (4x2) from Vegas to Denver to Cheyenne to Denver (all loaded) and back to Vegas (left car in Denver, but still had tools/etc). His trans temps NEVER exceeded 170. Even on long grades where coolant and oil went into/over 230, his trans was locked on 170. I haven't done the research yet, but I do want to see if the 6.4 2500 has a different/bigger trans cooler than the 1500 5.7 (or different trans altogether). If its the same trans, then it has to be the cooler. By contrast, on a 10 mile errand yesterday I saw trans temps up to 194 yesterday in a completely empty truck. It is Vegas, air temps were about 104, but still.
Edit: I did look up the coolers - for the 1500 5.7 the part number is: 68312697AC For the 2500 6.4 it is: 68322494AC. So definitely different P/N/s.
