I'm sure y'all have heard this before, but im stumped. 99 Sebring Coupe, 2.5L 4sp auto w/OD, slips trying to go into third gear, speedo works, if i play around with it a bit it will catch in second and not slip but WILL NOT shift into third. Mil light on, codes P0700 and P0733. So far i have changed; crankshaft pos sensor (no start condition), EGR valve (rough idle condition), input and output speed sensors,changed fluid and filter and added Lucas, TCM, 3 relay pack on firewall, in that order but not all at once. After all of that it is still not fixed. SO... in your professional opinion what would be my next step, replace the tranny? And is there really a splice between the solenoid, tcm and relay?

 

Rather than randomly buying replacement parts, get the car hooked up to a real code reader and see what's going on. That P0700 code is a message telling you that there are fault codes stored in the computer that can be read with the proper equipment. That does NOT include the code reader used by the guys down at the parts store. A good transmission shop will be able to read those codes, and also do a pressure check to see if there is something wrong in the pressure circuits.
The car is going on 13 years old and may be due for some serious transmission work. But replacing the transmission is a very big expense, so get it in somewhere where they have the equipment and know-how to diagnose it properly. The car is running so the possibility of shopping around still exists,

 

I ran into the same problem you're having on my 97 jxi convertible. The reader that I had said it was the overdrive clutch or something with the overdrive. I contacted a shop manager from a dodge/Chrysler shop in my area and the guy said that it was more likely that that something in the transmission broke or just wore out. Fortunately for me I had a parts car so I went ahead and just swapped transmissions. It took me about 30 or 40 hours to do it by myself. But this is my first tranny job ever and I even had a four point lift to my disposal. But now it's fixed and over with. If you can find a tranny cheap enough out of a junk car just swap it and sell the thing. I've personally invested thousands into mine just so I can get back and forth to work and I've had it for 2 1/2 years.

My total for the car--- 2800
My total to fix the car(before trAnny)--est 2430.