Vacuum problems? I have a vibration noise and a whistle under the dash of my 2005 Trailblazer after it warms.I have had the entire dash out of it and cannot find where the noise is coming from. It makes this noise when the rpms are neutral. When I accelerate or let off it stops.

SOURCE: loud noise with vibration

Your impeller is almost certainly cracked or shattered. I just changed mine today after I sucked up a small 1/4" screw. Unbelievable how much damage a tiny object can cause! The kit can be purchased at the popular online auction. I got mine from seller "cleaner48" for $18 with S&H. Get the kit with the latex sealant included. This is a must or your machine will blow dust all over. The seller's site gives instructions but he also sends them with the kit.

The repair took me 1-1/4 hours. I needed a Phillips screwdriver and a medium flat head screwdriver. Not too hard. You must remove about 12 screws and 3 large parts to get at the impeller.

-Mark

SOURCE: Loud whistling noise from back of vacuum

On the back side of most kenmore vacuums, there is an air relief diaphragm that, when the motor is sucking but there is no air flow, will pop, causing the sound you heard. check your hose for blockage, check your bag and or filter for blockage,even your attachments/wands can become lodged with debris. Often, after a few, the motor will get hot and the machine will shut down. This is a thermostat on the motor that protects it from overheating. I am quite sure that this will solve your kenmore woes, fine choice in vacuum, kenmore, tried and true. hope to have helped! Have a super, and hopefully sucking(ha ha) Sunday

SOURCE: Flair Cleaner makes squeaking noises

There are two items that could squeak:
If it squeaks when pushing/pulling it on carpet, WHILE NOT RUNNING, then the wheels are squeaking when they rotate on the wheel shaft. If so, one drop of oil at the shaft would fix it.

If it squeaks WHILE RUNNING, mostly while pulling backwards on carpet, then the belt is slipping. You may wish to set the nozzle height setting for a higher pile carpet, or could replace the rubber belt.

SOURCE: whistling noise on dc25 Animal

there may be a small cut in the tube or there is something stuck restricting the suction check all hoses