Hi guys on my 2006 Mustang GT. I have 88,000 miles and not sure if my rear end difrentual fluid has ever been change. Do you guys think it's a good idea to have it change...Thanks.

 

Not if the gears are quiet. If beginning to whine a bit, can't hurt to change it. My '04 has 170,000 on the original fluid, still quiet, never touched.

 

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If the car's service history is unknown, it's always a good idea to replace all fluids and filters so do it.
You'll need 3 quarts of 75W-140 rear differential fluid plus a bottle of friction modifier. If you wait until the gears become noisy, it would be too late and you'd end up needing to replace them.
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Be sure to use rags and or paper towels so you can get rid of them quickly. The smell is very bad

 

Implying the gears will not become noisy if fluid is changed is a fallacy.

 

Nevertheless it can't do any harm to change the fluid if it hasn't been changed since the car rolled out of the factory. The bearings and LSD would also benefit from having fresh lube with friction modifier. It's preventative maintenance.

 

Beware! Though you are totally correct, there exists no such word as "preventative". It's "preventive". That fact cost me on a technical paper I had written.

 

The word preventative does exist and we use it in medicine quite a lot. It has the same meaning as preventive so the two terms are interchangeable.

 

Then whomever was reviewing the paper was just being a dipswitch....

From Websters dictionary site.
"There is no difference between preventive and preventative. They are both adjectives that mean "used to stop something bad from happening." Both words are commonly used in contexts concerning health care, as in "preventive/preventative medicine." Preventive, however, is used much more frequently than preventative."

https://www.merriam-webster.com/word...0preventative.

To the OP, I agree with Dino Dino, fluids are not something that should be left to the "If it ain't broke don't fix it" mentality. Fluid changing are a preventative measure to avoid mechanical breakdowns. Without knowing the history of the vehicle, when in doubt, replace the fluid.

 

Yes, change the fluid. Use a good quality synthetic. Through the natural process of wear, small particles build up in the oil, and changing it will reduce the rate of wear going forward. Full synthetic will also reduce power losses, and increase your fuel economy.


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