Ford: 1999-2000 E-150, Expedition, F-150
Lincoln: 1999-2000 Navigator
Issue:
A chattering noise from the rear axle may be heard when turning or cornering. This may be due to differentials containing clutch packs that have been gauged too tightly.
Action:
Install new Traction-Lok clutch pack kit. Refer to the following service procedure for details.
Service Procedure:
1. Confirm axle chatter with road test.
2. Once axle chatter has been confirmed, remove and discard old clutch packs, shims and Belleville springs. Refer to the appropriate workdshop manual for details.
Note:
Subtract 0.25mm(0.010") from feeler gauge reading taken during shim selection using service tools and procedures indicated on instruction sheets packaged with kits.
3. Install clutch pack kit F75Z-4947-AA for 9.75" ring gear traction-lok axles or clutch pack kit F75Z-4947-AB for 10.25" ring gear traction-lok axles. For ring gear size and differential type, see embossed metal tag attached to rear axle cover. Refer to the appropriate workshop manual for details.

This is covered if your truck is still under warranty. 2.2 hrs. are allowed for drum brake axles. 2.4 hrs. are allowed for disc brake axles.