I have a 96 xj sport and I pulled a small 4x8 trailer unloaded about 20 miles in 60 degree temp. and my transmission got hot enough it pushed transmission fluid out the dipstick. I pulled in overdrive on the highway at 60 m.p.h. Why did the transmission get so hot? I have a transmission cooler and fluid level was good. Should I have not pulled it in overdrive or is there maybe something wrong with my transmission cooler?

 

How much does the trailer weigh?

 

I move it around by myself and it is very lightweight.