w1ayne

In my 1991 LS 400, the drivers window went half way up and stopped. It would not move from that position. When the window regulator was removed I expected the glass to need support to prevent it dropping to the bottom of the door. But that was not the case. Instead it was tight enough in the rails to remain in place ( in my Mazda 929 when the regulator was removed I had to support the glass). This lead me to believe that the glass in the runners was tight enough to stain the motor to the breaking point.

I installed a remanufactured motor and measured the ampere used while raising the window (see the picture below for the setup). It was 5 amp which is less than the service book value of 7 amp, so the motor was not staining. Upon disassembling the gear part of the motor, the plastic helical gears at one spot were ground thru by the metal worm gear and it stuck there ( see picture). It appears the worm teeth were only 2/3 (or less) into the helical teeth, while from the internet it appears they can be almost to the bottom. The worm gear has only about 0.01” play away from the helical gear so the gears “walking” away from each other is not a factor here (in a remanufactured motor wear in the case for the end support of the worm may be enough to allow “walking” away of the gears causing less bit between them). It appears it was manufactured for the gear teeth to not engage more deeply (??). But this motor has worked for 137,000 miles, so I am a little confused as to why it failed.

dicer

Did it have any grease on it? That is one of the areas that Lexus pursuit of perfection fell short, just like the pot metal door handles that break.

w1ayne

It was well greased. I cleaned it off to take the picture.