I recently acquired a 1999 450ES with just 82 hours and 890 miles. It's extremely clean and well maintained,however it was plagued with ES shift problems. Lots of research(mainly this forum), I decided to remove all the plastics,go over all electrical connectors,and clean and lube the shift motor and gears. Everything went smooth. The shift motor armature was black colored where the brushes make contact,and there was barely any grease on the shifting gears. Using alligator clips to hold the brushes is a great help,however when putting the housing on it'll suck the armature right out!! After about 3 times of this happening ,,I GENTLY applied vise grips to the gear on the end of the armature to hold it into the brush housing,,BINGO ! Slid the housing over the armature and got the bolts in. Hope this helps someone...especially if you're doing this by yourself !