Subaru Differential bearing - When to replace?

[needsducktape]

My 2001 Subaru Forester started humming just like wheel bearings when they start to go bad.

I just replaced the rear passenger side but so when it started humming again last weak, I thought it may be the driver side rear. Turns out it was the differential bearing. And I will likely need to replace the whole rear differential.

I have seen bad wheel bearings last (My friends Toyota Rav4 has needed a wheel bearing since February )

Would I be taking a risk if I let it go for a month or two? Its not loud just kind of a light drone at this point.

 

[Rand]

how sure are you of the diagnosis?

could even be the wheel bearing you just replaced.. many of them are junk.

 

[stephen9666]

+1 on wondering how you know.

Could it just be low on fluid or need a change? Although if it's low and making noise, it may be shot anyway.

I'm not familiar with this app, so I could be way off base.

 

[Chris142]

If it is a bearing in the diff the longer you drive it the more damage will be done.catch it early and you may get away with just bearings. Let it go and that metal in the oil will ruin the gears too.

 

[Slacker]

Cannot help you with the bearing information you seek but if your Subaru is an L trim, you may want to find a rear end from an S trim. It will have limited slip.

 

[default]

Subaru open rear diffs are a dime a dozen, drain and fill with a Xw140 until you find a good used replacement.

 

[needsducktape]

My mechanic will just replace the whole differential for about $400 it will be a used low mileage one. I am supposed to go on a 600 mile round trip though and I would like to do it when I get back if its safe????

 

[needsducktape]

Originally Posted By: Rand
how sure are you of the diagnosis?

could even be the wheel bearing you just replaced.. many of them are junk.


My mechanic put it on the lift and listened to the wheel bearings, differential, etc with a stethoscope.

 

[default]

Depends how loud it is, if you filed it with heavy Xw140 gear oil, it would probably go another 600 miles. Though this is a not a difficult job, shouldn't take more than a few hours for a mechanic with a lift and power tools to swap, so why chance it?

 

[JTK]

I'd replace it as soon as possible given the results of failure can't be pretty, especially away from home.

 

[JethroBodine]

Originally Posted By: needsducktape
My mechanic will just replace the whole differential for about $400 it will be a used low mileage one. I am supposed to go on a 600 mile round trip though and I would like to do it when I get back if its safe????


It is safe but the bearing going bad can shed debris in the oil that will ruin all of he bearings in the system.

 

[andyd]

I would make sure it isnt the wheel bearings. Top off the diff lube and drive gently those 600 miles.

 

[needsducktape]

Just thought I would update everyone and say that the Subaru has made the journey reliably

800 total miles
Average fuel economy of 30.62 miles per gallon (highway cruising around 70mph)
Regular unleaded
Oil was changed a day before the trip