Why has my Ford Explorer V-6 differential whined since the day it was new? (SUV Ford Explorer Transmission)

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Question Details Asked:Apr 25, 2010 - 04:50 PMStatus:Closed

waters2	Why has my Ford Explorer V-6 differential whined since the day it was new? The entire differential was replaced under warranty at about 30,000 miles. The replacement differential also began to whine after 36,000 miles and has whined ever since. Replacing the special friction reducing oil in the differential helps, but the whine never goes away entirely and gets louder until the next differential oil changes with the friction modifier. One blogger suggested replacement of the entire differential with a Eaton Detroit model differential. I called Eaton and they suggested replacing the ring and pinion gears. The cost of about $1500 including labor is an estimate by my local Ford dealer, but they only install their own parts. Any suggestions? Should I keep limping along and ignore the noise?
	In Vehicle Type > SUV In Makes & Models > Ford > Explorer In Maintenance & Repair > Transmission 1 answer - 1119 days ago
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Answers

karjunkie 04/26/10 9:10 am PST

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

Vehicles:

2002-2005 Ford Explorers
2002-2005 Mercury Mountaineers

Issue:

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

Action:

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

Time: 6.6 Hrs for Explorer/Mountaineer

I agree with Eaton advice that you need to replace the ring and pinion gears and the bearings. Apparently the problem was caused when Ford did not press the bearings incorrectly causing movement in the gears and the resulting whine.

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