2003 Dodge Ram turbo diesel 5.9 l 24v crimson won't switch gears why?

What is your question?

Going down at freeway 60 it jerks like it won't switch gears going to 65 jerks back to 60 with a loud noise then let's go off and on I have changed my transmission speed sensor and change my fluid for the rear and front differential and it goes to jerking 30 40 50 and 60 can someone please help thank you

What makes this problem better or worse?

He gets better when you don't Ride it for a while and it gets worse with Drive driving more than 15 minutes

How long has your 2003 Dodge Ram 2500 had this problem?

Two weeks