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Ask Jared D Your Own Question
Jared D
Jared D, ASE Certified Technician
Category: Subaru
Satisfied Customers: 1515
Experience:  Shop Supervisor at County Fleet
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After changing my rear differential fluid it started making

Customer Question

After changing my rear differential fluid it started making a whine at high speed when not accelerating.
96 Legacy outback 2.5 153k
Submitted: 1 year ago.
Category: Subaru
Expert:  Jared D replied 1 year ago.

What type of fluid was used in when you changed it? Synthetic, conventional, what viscosity?

Customer: replied 1 year ago.
Don't know but I put the original fluid back in and the whine is still there.
Also noticed that the shop that just changed my front wheel bearing swapped the left side tires and not the right. They are the same brand model and size but slightly different tread pattern
Expert:  Jared D replied 1 year ago.

If synthetic 75w90 wasn't used you will definitely get a noise.

Also if the tires are different at all it can not only make a whine noise, but I have even seen them blow out the differential if driven enough. I had a customer replace only the front wheels of her subaru and left the rear wheels because they were only about 60% worn. It caused so much heat in the differential that it melted all of the seals out of the differential and melted the rubber mounts that hold the housing.

Expert:  Jared D replied 1 year ago.

I would make sure that all of the tires have the same tread pattern and then I would take a string and measure the circumference of each tire. If one or more tires is off more than 1/4 inch from the rest, it needs to be replaced.

Expert:  Jared D replied 1 year ago.

Hi,

I just wanted to see if you need any additional information.

If not, please don't forget to rate.