AS Greg said it's probably your gear. It could also be a combination of the gear on the motor & the teeth on the arm it runs on.
I've fixed more than a dozen of them in my area (mine twice in 12 years). You need to take out the entire mechanism out of the tailgate. After removing the tailgate panel you need to unbolt the mechanism & work it side to side until you get the arms out of the window tracks. Remove the window. Rebolt the mechanism with one bolt that has the ground wire attached & move the arms until the hole in the right center gear (as you look at the mechanism) lines up with a hole in the body of the mechanism. I have used a screwdriver to put in the hole & then tweaked the arms up locking the arms with the screwdriver. You need to do this to take the load off the motor. Remove the mechanism from the tailgate.
You will need a couple of things. One, access to a welder or someone that will weld up the material on the arm that runs on the motor. Two, either a replacement gear for the motor or a new motor. You can use any passenger side electric motor from the late '80's to early '90's celica's, cressida's, or corolla's (I know these ones will work but only from the passenger side). If you get one of these motors you need to switch the connectors (wires may be different colors, so make sure which wires make the motor go one way & match the new motor). Most times you will probably break one or more of the three bolts to remove the old motor, so I usually get the replacement motor first (in the car doors they usually look brand new & bolts come right out easily).
Get the arm gears welded (at the end of the arm you will see the gears worn down) & file them back down to match the motor gear. Instal the new motor & replace the mechanism in tailgate (don't forget to tweak the arms & remove the screwdriver). Replace glass.
You could do one or the other of the above two steps & your window will probably work for awhile, but it will wear out quickly. I would recommend doing both of these steps. I use my rear window all the time & it lasted about 7-8 yrs between fixes.
Motors for the tailgates in my area are about $100 USED!!! Passenger door motors...$25, same motor, different connector, BIG difference in $$.
I've charged $125-$250 to fix the rear windows, takes me about 1-2 hrs depending on how bad the gears are ($250 was to find another mechanism, he broke one of the arms).
I hope I've remembered everything. If you have anyother questions PM me.
Jeff <img src="/forums/images/graemlins/cheers.gif" alt="" />
