Rear diff whine
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Rear diff whine
Hello everyone. I have a 2017 F150 3.5 ecoboost with just under 88k miles. Had my rear diff fluid changed at 85k and it’s developed a whine. The gears looked great and the recommended motor craft diff fluid went back in. Could low fluid be causing this or is my diff already going out? Thanks to everyone!
Laughing Gas
Joined: Mar 2008
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From: coquitlam,BC
Hello everyone. I have a 2017 F150 3.5 ecoboost with just under 88k miles. Had my rear diff fluid changed at 85k and it’s developed a whine. The gears looked great and the recommended motor craft diff fluid went back in. Could low fluid be causing this or is my diff already going out? Thanks to everyone!
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I believe it was 75w85. Would I be ok to top it off with Marvel mystery oil since it won’t be much at all? I don’t wanna put the wrong weight in it!
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I had my buddy that’s a certified mechanic do it for me on the side so no warranty claim will be happening. Just trying to make the whining less apparent
Fleet Owner
Joined: Jan 2004
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From: Brentwood,CA
The diff requires 75w140, if its whining its on the way to destruction already.
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is their anything I can do to help it? I’m trying to prolong it since I’m looking to trade it in
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Laughing Gas
Joined: Mar 2008
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From: coquitlam,BC
Then replace the fluid with 75-140 synth gear oil.
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From: GA
Ummmmm, why would your buddy who’s a certified mechanic put the wrong fluid in the differential. 🤔
Fleet Owner
Joined: Jan 2004
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From: Brentwood,CA
Possible low fluid and wrong fluid used. What was the point of this service? We wonder why Ford took the transmission dipstick away. When I did service work I couldn't believe what people and indy shops would use for service. Often it's better to just let the lifetime fluid ride as this didn't do any favors.
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From: Isanti, MN
Lead Driver
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From: Mts. S. of San Francisco
Back in the 60s and 70s guys would throw a banana peel in the diff to kill the whine. I'm betting this might have worked temporarily if you were trying to get a quick sale, but probably not much more than that.
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From: Isanti, MN
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