Rear axel whining noise like a bearing when your accelerating an d just cruising at normal speeds on highway

A loud whining noise on acceleration in a 2010 Mazda Tribute could be a sign of a few different issues. Here are some potential causes:

1. Power steering pump: A whining noise can be an indication of a failing power steering pump. The noise may increase when the steering wheel is turned.
2. Alternator: If the whining noise increases with engine speed, the alternator may be failing. This is because the alternator is responsible for charging the battery and powering the car's electrical system.
3. Transmission: A whining noise during acceleration could also be a sign of transmission issues, such as low transmission fluid levels, worn bearings, or a damaged gear.
4. Differential: A whining noise that increases with speed could also be a sign of a failing differential. This is the part of the car that transfers power from the engine to the wheels.

It's important to have a professional mechanic diagnose and fix the issue to prevent further damage to your vehicle.

The whining noise could be for many reasons. Narrowing the possibilities depends on when the noise occurs. If it happens only while decelerating at any or all speeds is most likely caused by bad pinion bearings or loose pinion bearing preload. If it happens during acceleration over a small or large speed range is usually caused by worn ring and pinion gears.

One cheap thing to check is the fluid level in the differential. If low, topping off the lube may help for a while.

One wheel turning faster than the other is normal if both wheels are off the ground. If one wheel is dragging when the other wheel is on the ground, it could be brakes or a wheel hub bearing.
Usually if the noise happens on right turns, the left hub bearing is failing, and vice versa.

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a whine noise you might want to check your wheel bearings bad axles make knocking or clicking sounds more than a whine

Here are the common causes or rear end noises
Constant high pitched whine at all speeds: Pinion Bearings or Ring gear carrier bearings
Whine at steady speeds or whines on deceleration: Rear end gear set is worn and will need to be replaced.
Rumbling type of noises are caused by wheel bearings or a tire with a separated cord.

The rear end and the transmission are possible to blame. The rear end jacked up and on jack stands with both or all wheels off the ground . $ wheel drive needs all wheels to be up on alevel hard surface in a quite place. With a driver in the truck driving at the speed the noise is loudest listen to each partt with a broom handle pipe Ect. the rear ends are most likly and the noise changes from slowdown or speedup. Lack of lubercanrt would be nice or jast a bad wheel bearing ( grab the stopped wheel and try to move it up and down ) No play should be found and turn smooth, in and out a little is normal and the brakes on or off shouldn't changany thing or they are suspect. Driveshafts click pops and ring not wine. Trannys get bad bearings if they do you may have noticed other trans related problems as well. When trannys whine they do bad things are are getting ready to. Somr driveshafts have a carrier bearing are two piece and have a U joint in the middle. Listen to the sounding rod while running touched to this part and it will be a for sure if its bad

Sounds Like Pinion Bearings , But Carrier Bearings Should Be Replaced (In My Opinion) as they Could Be Contaminated

Well you can remove the sensor in the diff and make sure that looks ok they g obad quiet often also woulnd not hurt too remove the rear diff cover and inspect the rear end if it is whining and you dont see anything wrong i would refill it with lucas oil/grease and start praying check the pinion too and see if it has any play in it

Id get a mechanic to look at it. Sounds like a rear end bearing problem. Axle bearings pumpkin bearings.