If this type of noise that it is making, then there is a service bulletin related to the noise which is shown below. That being said, I have seen many of these trucks (with the converter rattling) run for years without replacing the torque converter and without causing any problem. Steve
A "rattling" noise in the converter housing area when the torque converter clutch is not engaged may occur on some vehicles. This may be caused by impact between the converter piston and cover spline teeth internal to the cover.
Replace the torque converter. The revised torque converter incorporates a new piston and damper design which reduces the possibility of impact between the clutch piston and cover spline teeth. Refer to the following Service Procedure for details.