No Suction in Hoover U6450-900

Probably belt burning due to a roller jam.
Take a look.

Your filter may be stopped up and not allowing vacuum.
Your discharge may be blocked. In order to have vacuum you have to have a way to discharge the air.
Possibly your motor is weak

I found this info
Why is my vacuum losing suction?
A motor generates power which powers a vacuum which, in turn, creates suction to lift debris. The most common areas of suction loss are within the hose itself, the vacuum bag, clogged rollers, broken vacuum belt or a faulty gasket. All of these problems will lead directly to the vacuum cleaner losing suction.

If the noise is coming from the motor area it could be your motor is bad.

pets in house? check all hose passages for "hairball" clog...and check the drivebelt that spins the brush...(some have an electric motor to spin the brush, thus no belt)

Pump fault? any filters which can be cleaned?

Air passage from back of brush head, through the joint, and up to bag, may be blocked.

vax power pet 1 filter keeps getting clogged up so dirt not going into cylinder

try to clean between the roller and the tube to the hose

With the unit standing upright, double check the clear plastic air passages on the sides of the vacumn to see if they are clogged.

Check to make sure you hear the vac. motor is running when in that position. The switch in the handle could be bad if it is not.