grilledcheese101

Ok,here is my problem....Im driving down the hiway and go to downshift and it made a high pitch squeel from the tranny (like I was trying to slam it in reverse sorta)and if I give it more that 1200 rpm's it feels like the rearend is going to squeel/shudder itself off.No matter what gear,if it gets to much accelleration,it grinds untill you let off the throddle.If I baby it REAL slow,I can get it up to like 1500 rpm's and about 4th gear-thats it.It goes into each gear like normal,and only screetches and cuts out under a load.The driveline wont spin when it does this as well..Im stumped-the fluild levers are good,and I need to be pointed in the right direction if anyone can help me out.She looks so **************** sexy and I cant touch her!!!! HELP!!! Thanks guys.