Rear Diff Whine

[Jeremy W]

While accelerating it sounds like my rear diff is whining and the noise increases as I accelerate. Anyone had any experience with this? Just started yesterday and I really started to notice it today. From what I've read it sounds like it could be the rear pinion bearings. Thoughts?

 

[NASCAR Mike]

Any leaks from your diff case? Does it get quieter after it warms up? How many miles on it?

 

[Black]

Change your fluid and use Amsoil Severe Duty gear oil.
My Explorer did this shortly after I bought it with 56k miles. Changed the fluid it was a touch milky.
Swapped the fluid whine was gone. Swapped fluid at 100k and 150k with no more milkiness or whine. Sold it 2 years ago to a buddy and he still has not had an issue.

Hopefully it is a fresh issue and the fluid swap will help and it has not been grooved yet.

 

[1955moose]

Black hit it. Be sure you add the Ford friction modifiers, don't know if Amsoil has one that works. The oil itself is a good one. Can anyone comment on Amsoil using a non slip additive that works as well as Ford's? Obviously this is for non slip diffs, with clutches inside.Check your vin# should tell you.

Sent from my N9131 using Tapatalk

 

[Black]

Amsoil used to claim you did not need friction modifier with their gear oil.
They have since backed off that saying some diffs may still chatter so they have released their own called slip lock I believe. I have not been able to source it locally even at the places that always stock your usual weight Amsoil gear oils. So I always just bought Ford friction modifier since the dealer always has it at $6 a bottle and not worth paying shipping for the little bottle.

 

[lbv150]

My '04 Expy had a rear diff whine since it rolled out the dealership 175,000 miles ago...still running fine. It's the gear lash shim setting from the factory. Was not worth fooling with.

 

[1955moose]

You'd think dealers that sell the oil would sell the additive. If I was a selling dealer, how hard or expensive to keep a box of the stuff. I agree, doesn't make any sense to spend $9.99, then pay another $6.00 to ship it.

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[Jeremy W]

Any leaks from your diff case? Does it get quieter after it warms up? How many miles on it?

167K miles and no leaks. Had a leak a little over a year ago and had the pinion seal replaced. It's run fine up until now. The whine starts around 30mph and increases steadily to about 50mph and remains constant.

 

[Jeremy W]

Change your fluid and use Amsoil Severe Duty gear oil.
My Explorer did this shortly after I bought it with 56k miles. Changed the fluid it was a touch milky.
Swapped the fluid whine was gone. Swapped fluid at 100k and 150k with no more milkiness or whine. Sold it 2 years ago to a buddy and he still has not had an issue.

Hopefully it is a fresh issue and the fluid swap will help and it has not been grooved yet.

Fluid is only a year old. Had the pinion seal replaced a little over a year ago.

 

[Black]

It is cheap and easy to do.
You have a new developed whine certainly worth doing especially if the whine was developed after the pinion seal replaced. A whine and noticeable dripping fluid are sometimes sign of a failing seal.
Seal could have been installed improperly and moisture could be getting in.