One problem related to transmission shudder has been reported for the 1999 Buick Lesabre. The most recently reported issues are listed below.
My 1999 Buick Lesabre VIN 1g4hp52kxxh421760 transmission shudders hard sometimes when I accelerate on wet pavement. It also does this if I don't come to a complete stop for several seconds. It did this with only a few miles on it, but when checked by the auto dealer service personnel of course they failed to find this defect and wouldn't repair my transmission. I complained twice but to no avail.