Hi all,

been trying to find a similar post so i don't waste other's time but unable to.

 

here is my problem:

 

growl from what sounds like both rear wheels when in gear and off the accelerator. Really easy to hear when travelling about 40 mph and you take your foot of the gas. If you put the clutch in or take it out of gear the sound goes away immediately. There is no sound when you are accelerating even at a light cruise, only when you come off the gas completely. Nothing is in the wheel wells or wheels like snow. The rear diff looks good and fluid is at a normal level. Sound could be coming from the center of the car but really hard to tell. I think it's from the rear wheel area and so do other passengers.

 

oh, it's a 99 legacy outback manual with 198k on it. new motor though.

 

both front axles are new. rears are not and unknown as to when they were replaced....

 

thanks so much,

mike

Edited January 28, 200917 yr by Stickboy42

are you feeling any vibrations at all? it sounds to me like a bad driveshaft ujoint or carrier bearing but that almost always has vibration, not just noise.

 

if it's noise only i'd guess the rear diff.

 

if there's any vibrations i'd guess the driveshaft ujoints. a rare driveshaft issue would be the center carrier bearing.

 

if you pull the driveshaft it should be easy to tell, the bad joint will be very lumpy feeling when moved or seized. there's a chance you can tell just by crawling under the car and looking.

 

have a very bright light handy so you can see signs of wear or looseness. grab the driveshaft and try and shake it. if it's loose then that's your problem. if not then the joint could still be bad you just won't know until you take it off.

 

be sure to check both halves of the driveshaft, basically anywhere you see a ujoint.

no vibrations at all, just noise. i'll get under the car tomorrow and give the driveline a peak and see if anything rears it's ugly head....

 

thanks again,

mike

Just guessing, here....have you checked the oil level in your diff?

Just guessing, here....have you checked the oil level in your diff?

you mean the front?

The rear diff looks good and fluid is at a normal level.

Sorry...totally didn't see that in the OP.

so the problem appears to be fixed.

i checked the u joints as best i could, no play and everything seems to move fine and smoothly...

what fixed the problem was apparently changing the diff oil. I checked it once again just to verify that it was fine and thought i'd change it for the heck of it. I put amsoil synthetic 80-90w gear oil in. the old oil was creamy colored and very thick (it had been sitting for 4 hours).

 

i drove it approximately 3-4 miles and could not make the sound come back. Does this make sense, i wouldn't think the rear diff would be that sensitive to oil age...

 

thanks again,

mike