Does the differential oil need to be changed ? - Ford Mustang Forum
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post #1 of 5 (permalink) Old 10-29-2019 Thread Starter
Vicious013's Avatar
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Does the differential oil need to be changed ?

Hey guys, so i'm going trough a maintenance period on my car where i replace every fluid and filter. But i'm not sure about the diff fluid. I checked the manual and it explicitly says :

Rear axle lubricants do not need to be checked or changed unless a leak is suspected - i don't see any leaks
The axle lubricant should be changed any time the rear axle has been submerged in water - it wasn't submerged into water

Now i'm a bit confused since most people say i need to change it around 30k miles but the manual says it doesn't need any change. Did you guys changed it ?

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post #2 of 5 (permalink) Old 10-29-2019
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The manual is usually right on maintenance needs since it is designed to make sure that Ford does not have warranty issues, so it does not "need" to be changed.

That said, it doesn't hurt to change it. If you do change it, use a good synthetic fluid (I like Mobil 1 but there are others) and make sure you have the correct friction modifier. Check the fluid bottle, many of them have the friction modifier already in it. After changing it, do some tight figure 8's in a parking lot to work the new fluid into the clutch packs; and if you experience any binding or jumping that does not go away after a few more figure 8's, then add more friction modifier and do it again.

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post #3 of 5 (permalink) Old 10-29-2019
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Needed? Maybe not according to Ford. Would I replace it? I sure have usually around 60-100K miles if no other issues caused to be replaced early.

Be sure to use the right fluid which I believe is trans fluid for most mustangs. Friction modifier is very important as mentioned.

I will say I have never heard of the figure 8 method, but makes sense. wish dealers or shops had told me about that in the past. Maybe would have helped...

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Last edited by MustangLife; 10-29-2019 at 10:07 PM.
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post #4 of 5 (permalink) Old 10-29-2019
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It does not need to be changed.

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post #5 of 5 (permalink) Old 10-29-2019
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MY 2006 GT maintenance schedule calls for it to be changed at 150K. I had mines changed around 130K.

2006 GT, Strut Tower Brace, Gas Hood Struts, FR Intake Plenum cover, Metal Fuse Box cover, Moroso brake reservoir cover, Rear shock tower brace, Front Bumper Lip Spoiler, JVC DVD Head unit w/ back-up camera, satellite Radio and USB input, 2 - 12" sub-woofers, 4 - 6"x8" speakers, 2 - 6.5" speakers to replace the door subs, 3 amplifiers, LED lights under the hood and in the trunk, chrome e-handle on parking brake handle, chrome cup holder trim, and trunk lid cover with running pony emblem.

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