I didn’t have the truck long before I had to remove the valance. So I don’t know if it has changed much but your logic sounds correct to me. If anything, because there are no holes in the valance, common sense makes one think that with the valance removed, more air would flow around the trans housing, motor and bottom of the radiator theoretically leading to cooler temps. I’m going to be towing a light weight camper this weekend (3000lbs) with a four wheeler in the bed and going up large grades so we will see if the coolant temp goes beyond 15 degrees. I doubt it will because in early July, I towed a Jeep on a trailer for 800 miles through the southwest in the desert heat and had the normal 15 ish degrees increase before the dampers would open and stabilize the coolant temp Towing the the Jeep, my trans temp rarely reached 200 degrees on the freeway/highway, mainly sat at 194-196. But get off the freeway/highway after towing for a while and do some stop and go and the trans will go up to 208/210 (95 degrees ambient temp) Sent from my iPhone using Tapatalk