One problem related to transmission sensor has been reported for the 1999 Chrysler Concorde. The most recently reported issues are listed below.
Transmission input sensor failed on my 1999 Chrysler Concorde lxi with 25,000+ miles causing the transmission to abruptly down shift causing vehicle to over rev engine which caused an abrupt slowdown which could have caused a rear end collision or a loss of control. Part id # is 4800878. Since my failure I have heard of 2 other failures just from people I've talked to. This is a problem Chrysler is aware of. They should be held accountable for any accident which this failure contributes to. A safety recall should be initiated. Just for info this repair cost me $161. 87. Pretty steep for a known problem!.