Seat Leon Steering, Suspension, Brakes, Wheels & Tyres Problems

Needed to screw in one of the pistons as it had came out fully, now only one side rear not working when engaged

Noise only there between 60-62 mph …had tires and wheel bearings checked…could it be gearbox?

Always screams when reversing and no and again on driving braking

I am on the motorway, I put the car in 6 th gear, 2 seconds later it pops out of gear, it does this every time as of late, it is a manual, can somebody please help and tell me the problem?? It's only 6th gear, feel like a hammer is knocking...