Drivetrain noise

[ivan12]

I need some serious help guys. My car is making an annoying noise and Im pretty sure it's from underneath and not from the engine. Here are my symptoms: "sometimes" or at any time I can hear a loud constant chirp or squealing as the car is in gear and moving, before it would do it in 1st and 2nd gear only but as time has passed it sometimes ranges all the way to 5th gear. Symptom 2: when I'm in 1st or 2nd gear Ill drive the car until around 3k RPM, in gear I'll let go of the gas and when I press the gas again I'll feel a bit of a thump on the shifter. This all started before I changed out my exhaust so I know it's not just my side exhaust banging around. At first I thought it was my throw out bearing since I could hear a distant whistle when the clutch was depressed. I also saw that I have an oil leak where the engine and tranny meet which I'm thinking is a rear main seal. I already ordered the TOB the retainer and the seal. Do you guys think it could be my tranny going bad or my clutch? Whatever it is I just want to do it once since I'm doing it myself and know that it's not going to be a 1 hour fix. I already checked the u-joints when I was under the car, I put the car in gear and moved the driveshaft around and there was play in the tranny but not in the joints. Could the joints still be a problem? Thanks for any help