1999 Dodge Ram Wont shift 40% of time

My symptoms:
1. Tranny wont shift at all, (reverse, fwd, 2, 1) about 40% of the time.

2. When trans working I get a shudder when the trans downshifts into 1st (like the truck wants to keep going, I have to apply more brake to correct this then it will finally downshift)

3. When shifting up from first the tranny causes a noticeable bump then accellerates and runs great.

4. When tranny won't shift you can hear a noticable shoshing sound coming from the floor of the truck. (Tq conv I'm guessing).

What in the world could be wrong and how do I fix it?

Thanks much!