2020 Freightliner vs 3500 GMC Dually at the Ike

The reason why they rise is because you do not have enough air for the amount of fuel you are burning so the best thing is to get as much dense air into and out of your engine as possible with the least amount of restriction of reduce fuel. If your EGT's are high when towing, downshift to increase rpms and back off the throttle. Increasing rpms moves more air in and out of the cylinders. Backing off the throttle reduces the amount of fuel being injected. Most if not all modern diesels will automatically do this if EGT's get too hot.

Mods like an intake, better intercooler, larger/more efficient turbo, and less restrictive exhaust are all things that lower EGT's.