AERA Members have reported a front end engine rattle noise on 1999-2009 Ford 4.0L SOHC engines. This noise is audible during hot and cold conditions, but is most commonly heard when the engine is cold under acceleration at 2400-2500 RPM.
To confirm the presence of this noise, put the vehicle in 2nd gear and accelerate the engine between 2000-3000 RPM and listen for a rattle noise that sounds similar to a spark knock. This type of rattle noise could be cause by the primary timing chain tensioner system.
Ford advises that the primary timing chain tensioner, chain guide, jackshaft and crankshaft sprockets be replaced with a correct repair kit. The kit will include all parts listed previously along with required fasteners, primary timing chain and front cover gaskets.
There are two kits offered to cure this problem. One kit is for an engine that has a balance shaft and the other kit is for an engine without a balance shaft. When ordering the replacement kit, make sure that the correct kit is ordered for your application.
Replacement Kit Number Applications
2U3Z-6D256-AA (balance shaft engine) 1999-2001 Explorer/Mountaineer 4X4
2001-2002 Sport/Sport Trac 4X4
EXCEPT engine codes 2G-960-AA & 2G964-AA
2U3Z-6D256-BA 1999-2001 Explorer/Mountaineer 4X2
2001-2002 Sport/Sport Trac 4X2
WITH engine codes 2G-960-AA & 2G964-AA