I have a 2000 grand caravan sport with the 3.8. It sounds like Chitty Chitty Bang bang when it's cold but gets quieter as it warms up. When I was replacing the oil pan gasket I could see that there was a crack in the firewall exhaust manifold.
Can't find any threads on how to replace. Any ideas or links out there that I'm missing?
Thank you!

 

EXHAUST MANIFOLD
REMOVAL
Disconnect battery negative cable.
Remove accessory drive belt. Refer to Accessory Drive section located in COOLING SYSTEM for procedure.
Remove generator. Refer to CHARGING SYSTEM for procedure.
Raise vehicle and disconnect exhaust pipe from rear (cowl side) exhaust manifold at flex-joint.
Disconnect down stream oxygen sensor connector.
Lower exhaust system to gain access to rear manifold.
Separate EGR tube from rear manifold and disconnect Heated Oxygen Sensor lead wire EGR Tube, Heated Oxygen Sensor and Generator/Power Steering Strut
Remove heat shield from rear engine mount.
Remove Generator/Power Steering Support Strut EGR Tube, Heated Oxygen Sensor and Generator/Power Steering Strut
Remove bolts attaching crossover pipe to manifold EGR Tube, Heated Oxygen Sensor and Generator/Power Steering Strut
Disconnect up stream oxygen sensor connector.
Remove bolts attaching rear manifold to cylinder head and remove manifold.
Lower vehicle and remove screws attaching front heat shield to front manifold Heat Shield - Front
Remove bolts fastening crossover pipe to front exhaust manifold and nuts fastening manifold to cylinder head. Remove assemblies Crossover Pipe
Inspect and clean manifold. Refer to Cleaning and Inspection in this section for procedures.
INSTALLATION
Install rear exhaust manifold and tighten attaching bolts to 23 N·m (200 in. lbs.)
Install generator. Refer to CHARGING SYSTEM for procedure
NOTE: Inspect crossover pipe fasteners for damage from heat and corrosion. Replace if necessary.

Using new gasket, attach crossover pipe to exhaust manifold and tighten bolts to 54 N·m (40 ft. lbs.) EGR Tube, Heated Oxygen Sensor and Generator/Power Steering Strut
Connect oxygen sensor lead EGR Tube, Heated Oxygen Sensor and Generator/Power Steering Strut
Install EGR Tube and Generator/Power Steering Strut EGR Tube, Heated Oxygen Sensor and Generator/Power Steering Strut
Install front exhaust manifold and tighten attaching bolts to 23 N·m (200 in. lbs.)
NOTE: If dipstick tube was disturbed, the tube to block seal may be damaged. To reseal the dipstick tube, remove the tube, clean, and reseal using Mopar® Stud & Bearing Mount Adhesive.

Attach exhaust crossover with a new gasket and tighten fasteners to 54 N·m (40 ft. lbs.) Crossover Pipe
Connect up stream oxygen sensor connector.
Install exhaust system.
Attach exhaust pipe to exhaust manifold using new gasket and tighten bolts to 28 N·m (250 in. lbs.)
Connect downstream oxygen sensor connector.
Install front manifold heat shield and tighten attaching screws to 12 N·m (105 in. lbs.) Heat Shield - Front
Install accessory drive belt. Refer to Accessory Drive section located in COOLING SYSTEM for procedure.
Connect battery negative cable.