When bulldozers work, the hydraulic oil in the gear box goes out and smokes. What is the reason?
You should first look at the bulldozer type; if it is a mountain of torque converter structure such as SD16 bulldozer, gearbox oil, high temperature will cause smoke, high temperature is likely to be the hydraulic oil in the oil string to the torque converter, through the torque converter into the gearbox;
The high oil temperature, of course, smoke, torque converter full of oil!
then you have to look at the hydraulic oil tank if the oil level is lower; lower for pump assembly or the pump shaft seal.