2003 Ford Explorer, differential Problems

Old 10-07-10, 10:13 PM
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2003 Ford Explorer, differential Problems

Ford Explorer 2003 4WD 4.0 6 cyl. A/T
I am getting a lot of noise from the differential. A machanic who worked for Ford for 12 years said you can rebuild them but the problem will return in about 15K to 30K miles depending on how you drive.

He said the problem is the housing (casing) because it's an aluminum housing that will expand and contract because of heat.

Anyone have any knowledge on this?

I looked at mine and it looks like that pot metal aluminum but not sure?

Wow! Lots of folks online I read have replaced their differental 2 and 3 times. Seems the problem group is 2002 thru 2004.

Duke of
Old 10-08-10, 12:50 PM
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yes-the rear diff does generate quite a bit of work for the shop.
i have repaired them (new bearings/gear set/seals)-since their introduction in 02 /i do not see a terrible repeat repair pattern.
you should get 75k on a good rebuild-always use the synthetic lube.

note- another miss diagnosed noise/bearing concern is the rear wheel/hub bearing.
Old 10-08-10, 03:15 PM
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Check with a dealer to see if the TSB below applies to your truck.

TSB 05-12-6 2002 Explorer Rear End Whine
Ford Explorer Rear End Whine/Hum


2002-2005 Ford Explorers
2002-2005 Mercury Mountaineers


Some vehicles listed above may have a whine/hum during acceleration, deceleration, and/or cruise.


Use axle repair kit to fix the issue. This kit should be used instead of installing a complete rear axle assembly. Replace the Ring and Pinion and it's components.

NOTE: When servicing the rear axle on these vehicles, replace the 75w-90 gear oil with 75W-140. If the axle is equipped with a Limited Slip, add the required amount of friction modifier (XL3). When replacing the fluid, replace metal tag with F3TZ-4121-AA tag.

Kit Part Numbers:

8.8" 3.55 Gear Ratio - 5L2Z-4209-AA
8.8" 3.73 Gear Ratio - 5L3Z-4209-C

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