One problem related to transmission solenoid has been reported for the 1999 Plymouth Voyager. The most recently reported issues are listed below.
Purchased used Plymouth in October 2007 with 5393 miles on the odometer. Registered and drove it from December 3, 2007 to Jan 2, 2008. Noticed significant amount of transmission fluid under the vehicle and film of fluid on back window and hatch area. Observed fluid pumping out from under the car. Mechanic tells me the solenoid block most likely has failed and will need to be replaced. I am told this is a "common" failure in later model 41te transmissions.