2018 Ford Expedition RWD Grinding noise from rear differential

[whizbala]

Hello -
I have a 2018 Ford Expedition RWD with the Heavy duty trailer tow package. The truck has 116k miles on it and i have only had it for last 3 months. There is a grinding noise from the rear differential and it seems to have increased in last couple months. It is both when accelerating as well as when coasting.

I did a rear diff fluid replacement last week with the morotcraft fluid and friction modifier, and it didnt help. The old fluid looked like in good condition with no metal fragments.

I am planning to do a swap of the rear diff instead of a rebuild. I am seeking guidance on what i should look for when selecting a replacement differential.

My differential tag reads - JL1W-4200-KA U55X 975 3E73. So i know i need the 9.75 ring rear and 3.73 ratio, but what does the 4200 and KA represent? When i search on eBay i am finding many diffs that have 9/75 and 3.73 but are JL1W-4000-LA and i am not sure if its a substitute or not?

Appreciate any help and guidance.

Thanks
Balaji

 

[Fastcar]

Hello -
I have a 2018 Ford Expedition RWD with the Heavy duty trailer tow package. The truck has 116k miles on it and i have only had it for last 3 months. There is a grinding noise from the rear differential and it seems to have increased in last couple months. It is both when accelerating as well as when coasting.

I did a rear diff fluid replacement last week with the morotcraft fluid and friction modifier, and it didnt help. The old fluid looked like in good condition with no metal fragments.

I am planning to do a swap of the rear diff instead of a rebuild. I am seeking guidance on what i should look for when selecting a replacement differential.

My differential tag reads - JL1W-4200-KA U55X 975 3E73. So i know i need the 9.75 ring rear and 3.73 ratio, but what does the 4200 and KA represent? When i search on eBay i am finding many diffs that have 9/75 and 3.73 but are JL1W-4000-LA and i am not sure if its a substitute or not?

Appreciate any help and guidance.

Thanks
Balaji

Are you sure it is the dif? No metal in the oil and the same noise under load as not sorta leads me to an axle bearing.

 

[wakeboarder]

A 2018 with the tow package will also have the eLSD.To confirm, you should see an electro-hydraulic actuator on the top of the differential.