When identifying the Chrysler Crossfire 722.6 converter, which is also used in the Jeep Grand Cherokee with 3.7L engine and Dodge/Freightliner Sprinter Van-type vehicle, be sure to identify the code number (last five digits) pin-stamped on the side of the unit. The Cherokee has a code of 478AA. Some noted differences between units include the stall speed, clutch damper design and pilot diameters, which is why matching the code is so vital when replacing the unit. By determining gas or diesel, it is easy to identify. Identification of the diesel converter, predominantly 2.9L, can easily be verified by measuring the pilot diameter. The diesel version is slightly larger (1.375) than the gasoline version and also contains two clutch plates.
Converter rebuilders should be aware of a few industry complaints: One, a low RPM vibration on acceleration; and two, a buzz apparently coming from the converter bearings and additionally clutch slippage. The vibration, while may be thought to be related to the converter, usually stems from the excessive length of the driveshaft, especially on the long wheel base Sprinter Van. As for the buzz and clutch slippage, it has been reported that water enters the transmission fill tube causing an area of concern. In addition, it is highly recommended to replace the impeller to stator bearing during rebuild due to known failures reviewed in Chrysler recalls.
If you have purchased one of many warranty returned converters, dispose of the bearing and replace the clutch liner even if physically no damage is visible. These items are known for failure, and inspection of the bearing does not reveal a problem.
While no permanent cure has been designed to resolve the vibration experienced by many drivers, one suggestion is to manually downshift the transmission to the next lower gear. This should provide customer satisfaction and improved driving conditions, but again, will not solve this issue. It is believed this problem will be solved by transmission technicians in the near future.
– Found in August 2006 Newsletter