Chucking out black smoke and losing power on incline

Hi. Checked under the bonnet a few months ago and a thick pipe had come loose which was causing the car to chuck out black smoke usually on even a slight incline, and gets 10 times worse putting into fifth gear. It is like there is no fifth and the turbo doesnt kick in. The pipe was fixed and was fine for 2months, but now it's happening again and it's worse.Also under the bonnet is a clear long pipe with a black rubber ball shape in the middle, and when i accelerate, the ball squeezes in and the fluid stops circulating. Stepping on the gas doesn't make a difference as the ball stays sucked in until physically touched!So much smoke comes out i'm lucky to do 70mph and then drops to 50mph on the incline.It's had a diagnostic check which says no problems. Filters changed 10months ago. Please help!! and thank you in advance to anyone who can help!