Center Carrier Bearing condition

[tbolt1003]

I've been chasing an intermittent humming and howling noise with my 95 Impreza L wagon with the 4EAT and 2.2. It isn't set at a particular speed, but doesn't appear until around 20mph, and changes if I am on or off the gas. Occassionally, at highway speeds, the whine becomes an ear-piercing howl that makes me slow down so the noise goes away. Every so often, I can hear a clunk/chatter noise and a wobbling sound and it sounds as though it's coming from right under the console. I crawled under and looked around. The rear driveshaft moves around a good inch within the center carrier bearing and where the shaft goes into the bearing housing on both sides is heavily corroded. Does this picture look like the bearing is shot? I realize the entire shaft needs to be replaced as an assembly and I've found a shop that has brand new ones in stock with greasable U-Joints. What does everyone think?

 

 

[Fairtax4me]

Only good way to check that bearing is to remove the driveshaft so you can spin the bearing by hand and see if it makes noise.

The rubber cushion around the bearing is soft and is easy to move around, that's normal.

 

More than likely your howl/whine noise is from one of the differentials. Try changing the diff fluids and see if the noise changes or subsides. Drain each into separate clean containers so you can check the fluid for sparklies.

 

The front pinion bearing is a somewhat common failure on the automatics, and can make a whining or grinding noise because it causes the front pinion clearance to change.

[tbolt1003]

Thanks, Fairtax. One other thing I noted is if I put the fuse in the FWD holder under the hood, the noise almost disappears. I can still hear the wobbly/clunk sound slightly, but the high pitched howl goes away. Figure that's because no power is being transferred through the drive line to the rear. I did pull the fill plug on the rear differential and the fluid looks clean with no metallic slivers, however I didn't drain and refill. I'll give that a shot and see if it helps.

[tbolt1003]

I changed the front and rear differential fluids and no change. The shop I take my car to for repairs has a Subaru specific mechanic on premesis and he did the fluid change. He said there was nothing abnormal in the old fluid, no metallic shavings, burnt odor or major discoloration. He feels the noise, which he heard during the test drive, could very well be the carrier bearing. He confirmed it's rare they go bad, but it does happen.