Here's the condition I had on my pre-owned '01 Ranger. The extended warranty folks paid for the repair, minus my deductible. Hope it helps.
Engine - Timing Chain Rattle Noise
RATTLE NOISE FROM PRIMARY CHAIN DRIVE AREA
2000-3000 RPM - 4.0L SOHC ENGINE
2001-2002 Explorer Sport Trac,
Explorer Sport, Ranger
This article supersedes TSB 02-08-01 to update part numbers and add a labor operation for vehicles with auxiliary air conditioning.
Some vehicles equipped with the 4.0 SOHC (single over-head cam) engine may exhibit a primary timing chain rattle noise. The noise is heard during hot and cold engine operation (but mainly heard on cold engines) under acceleration, typically at 2400-2500 RPM. To verify concern, accelerate in 2nd gear between 2000 and 3000 RPM and listen for rattle noise that sounds similar to spark knock. This may be caused by the primary timing chain tensioner system.
Replace the Primary Timing Chain Tensioner, Chain Guide, Jackshaft and Crankshaft Sprockets with a Primary Timing Chain Tensioner Kit. The Kit includes an improved Primary Chain Tensioner, as well as updated Primary Chain Guide, Primary Jackshaft, and Crankshaft Sprockets. Required fasteners, Primary Timing Chain, and Front Cover Gaskets are also included. Refer to the following Service Procedure for details.
Verify the condition. Obtain the correct Primary Timing Chain Tensioner Kit and follow the instruction sheet supplied with the Kit.
Use Kit 2U3Z-6D256-CA (balance shaft engines)
^ 1999-2001 4X4 Explorer/Mountaineer
^ 2001-2002 4X4 Sport/Sport Trac
^ ALL 2002 Explorer/Mountaineer, except engine codes 2G-960-AA and 2G-964-AA.
Use Kit P/N 2U3Z-6D256-DA (non balance shaft engines) for:
^ 1999-2001 4X2 Explorer/Mountaineer
^ 2001-2002 4X2 Sport/Sport Trac
^ 2002 MY Explorer/Mountaineer with engine codes 2G-960-AA and 2G-964-AA
^ ALL 2001-2002 Ranger
Labor Operation Claiming Chart
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
BASIC PART NO. CODE
Former Ride: 2001 Ford Ranger XLT Off-Road (Stock)
Current Ride: 2007 Toyota Tacoma Off-Road SR5 (Stock)