1993 Dodge Dakota problems?

I own a 1993 Dodge Dakota V6 engine with a 4x4 automatic transmission and has 160,000 miles on it.

My list of issues please help.

1. Here is a problem that has been bugging me for almost a year now. When I reach between the speeds of 55 and 65 my RPMs rise very high.

2. When I drive 65mph my rpms will be at 3,000 which is very high and I know that the rpms should be around 2,000 at that speed. The truck is wasting about 1,000 rpms of power.

3. Another issue is when I first drive in the morning or when the truck sits for a couple hours the rpms will rise high as the truck shifts almost as if the truck jumps into neutral. (makes a neutral sound)

4. When I go down steep hills I wont even touch the gas pedal I just let the truck coast down and what happens next is I will hear a kink sound then the truck slows down as if I touched the brakes. It seems like something locks up but the transmission stays in motion.

5. I noticed a rubber burnt smell coming from where the transmission is and I believe that might be my torque converter. Is it?

5. It seems like the transmission runs worse when it's cold outside like 20 degrees and runs better when it's hot out.

6. Oh and I hear like a rumbling thunder sound coming from the transmission area of the vehicle.

So far I replaced the speed sensor and did a transmission fluid change and no luck.

I already went to a transmission repair shop to find out the problem and the transmission mechanic was a jerk and did not help. Most of the mechanics in my area suck.

I'm just asking what could be the problem and I hope it's maybe one little part instead of the whole transmission.

Thanks