Bathroom vent lifting mechanism replacement parts

Are replacement parts available for the bathroom vents used in 2001. My motor works and will lift the lid but upon closing will not hold the lid closed. A close inspection shows the cast metal housing for the worm gear is bulged. I can't tell if the motor is attached and removable or a part of the greater assembly. Apparently the gears simply won't mesh properly. It all comes apart so I'm looking for a replacement for the worm gear box unit without motor if they come separately



ThanX all.



Roger from NJ.