I have a 1977 GMC Suburban with a power rear window in the tailgate.
It has become very hard for the motor to open or close the window and it makes a screeching sound when being operated.
Does the interior window frame need lubricated or is it rubbing on something?.
I know there is a access plate on the inside of the tailgate but the window denies access to the inside of the tailgate.
Is there a way to open the window when the tailgate is open so I can access the interior of the tailgate?.
Thanks for any insight.
More than likely the rear window regulator is worn out creating the screeching sound.
Your vehicle is so old, I can’t look up anything about the body/glass/doors on your vehicle on my on-line vehicle repair services.
I’d have to go into the shop and pull out the old Chilton big book manual for that year for that information. Which isn’t at hand.
Tester
Try lubricating the channels the window rides in with “silicone paste”:
Take the access panel off, then close the tailgate and the window. Lube the moving parts from inside the vehicle. There are a bunch of little wheels in there that need to move freely. Lube them and the rails they ride in. If the little wheels are gone you used to be able to buy replacements. I have no idea where I bought them when I did mine. Too long ago.
There is a switch on the passenger side of the tailgate that gets pressed when the gate is closed to allow window operation. Be forewarned, you do not want to move that window up and down unless the tailgate is closed. That’s a heavy piece of glass. Just do the lubing from inside the vehicle.
I used to rebuild these gates all of the time. What you will find when you take the panel off is you can unbolt the glass and then slide it out. There are plastic rollers that move the glass up and down. These are wore out most likely. If get lucky you can find the rollers at the dealer. If not you will have to buy the regulator. Replace the side runs too. You can sill get them on line. Keystone should have them.