Transmission getting hot?
 

I have a 2000 blazer 4x4, auto. Has 106k. I havent had this car very long, and we have put the tcc pwm and a shift Solenoid on. We also changed the filter and fluid. Before we changed all of this, i would notice that driving it for 10-15 miles at a time, it would get hot. Had a P1860 code.The truck would feel like it had a drag on it, like you are holding the brakes and gas together, and it would have a nasty smell to it. Since we put the solenoids on i can drive it around the city all day and not have and of the said problems, but if i drive it around the city, then get on the express way, i would have the same problems. No codes are being thrown anymore, it shifts and everything fine. Do you guys think putting a transmission cooler on this will help at all? Ive also noticed that it sound like the rear right wheel is making a sqweeling noise... could i have a brake dragging, making the trans get hot?

What is getting hot? What does it smell like? Have you determined the source of the heat/smell?

It could be anything from something as simple as a frozen caliper pin, a collapsed brake hose, or bad caliper to an internal problem with the trans, rear/front diffs, etc. There really isn't enough information in your post to determine what is going on.