97 aerostar awd rear end

hi my brother has a 97 aerostar awd v6 automatic, he says that the rear end is making a howling sound he checked the fluid added some the noise is still there, but wen turning left no noise from rear end turn right noise is there,or going straight. maybe some one has a idea what is going on in it thank you all
jenn

check the left side bearing

To check the rear bearing without posidrive. Block one side jack up the otherside about a couple inchs. The wheel in the air will run. Have somebody in the car run it in gear. You should hear a bad bearing.

how can you tell if it is a posidrive rear end, and the bearing you are talking about is it the axle bearing or a carrier bearing
thanks
jenn

Normally the axle bearing goes out first. Put a block around 3 wheels and jack up the other rear wheel about 2 inchs. Have somebody in the car put it in drive and the wheel off the ground should turn. Pick up speed to about 20mph you can hear a bad bearing. Then try the other side the same way. Even if posidrive this should work. If it wants to go over the blocks stop. Even with posidrive the one side on a curve will go faster. In the winter posidrive helps you to have power to both real wheels longer. In the worse case block up both rear wheels about 2 inchs and run about 20mph you should still hear a bad bearing. If unsure I would try this first.

Normally the axle bearing goes out first. Put a block around 3 wheels and jack up the other rear wheel about 2 inchs. Have somebody in the car put it in drive and the wheel off the ground should turn. Pick up speed to about 20mph you can hear a bad bearing. Then try the other side the same way. Even if posidrive this should work. If it wants to go over the blocks stop. Even with posidrive the one side on a curve will go faster. In the winter posidrive helps you to have power to both real wheels longer. In the worse case block up both rear wheels about 2 inchs and run about 20mph you should still hear a bad bearing. If unsure I would try this first.Not a good idea considering his is AWD, if you block the fronts and leave 1 rear up the van will still move...

My error I thought they were like a pickup where you normally don't use 4wd.
In this case put it on jack stands about 3 inchs high all 4 wheels. Run about 20mph you should hear a bad bearing.

Nope Aerostars are equipped with Electronic 4wd, the computer will see the rear wheel as moving and the front wheels as stationary so it will 'think' the rear wheels are spinning and kick power up to the fronts.