Welcome to our knowledge base of totally random and probably obscure stuff relating to 73-91 Chevrolet Suburban gear drive tailgate window motors!

We've recorded these notes and observations not only for ourselves (because we forget stuff over time), but also in case anyone else can find it useful. If you find something incorrect or wish to contribute something, just let us know here.
 GMT-400 door handles Information
 GMT-400 door handles Conversion to standard window motor



Note that this page refers only to the tailgates that use the gear-driven motor mechanism, not the cable drive. The cable drive motor is a stand-alone unit and cannot be substituted for the gear drive.

The gear drive motor for the rear tailgate is mounted behind the glass and arm mechanism. The glass must be raised or removed to access it. If the motor fails in the lowered position it is very difficult to raise the glass to access as it uses a worm-drive gear that cannot be moved backwards by applying reverse force.

The window motor for the tailgate is not the same as the unit for the door windows. The tailgate motor is slightly thinner in profile and longer in the motor body, as well as slightly different internally. Both motors use an electromagnetic drive rather than permanent magnets, and carbon brushes.

Tailgate motor part #: Cardone 42-21, UPC 00082617041560.
Standard door motor #: Cardone 42-16, or 82-016, or REP0468701, or OEM 22048629.

The motor is accessed by removing the inner plastic trim cover from the tailgate exposing the metal. The metal inside cover is then removed to access the tailgate internals. The window must be raised or removed in order to access the mechanism as all of it is between the glass and the outer tailgate skin.

Square body tailgate disassembled

It takes some time to remove all the parts to access the mechanism, so we recommend renewing the grease and lubrication on all the moving parts whenever the mechanism is accessed. A well lubricated window mechanism will help ensure a longer motor life.

             --Back to top--


Conversion to standard window motor

The tailgate window units are very difficult to find either new or rebuilt. For this reason we decided to convert a standard door window motor for use in the tailgate.

The door motor does not fit in the space allocated between the tailgate outside skin and the window arm assembly without modification. The motor head casting is slightly different in several ways that make it larger. The same removable gear drive assembly may be interchanged between the two motors however.

In order to make the door motor fit and work, the only modification necessary is to cut short the three bolt tabs that hold the motor to the arm mechanism. Note that this removes the centering indent on the end of the tabs, so the motor must be carefully centered by hand as the bolts are tightened so that the gears engage properly with the window mechanism.

First we measured the amount of material to be removed, then scribed the cut marks:
Square body tailgate window motors

Using an angle grinder, we carefully shortened the bolt tabs:
Square body tailgate window motors

We cleaned the shortened tabs with a file and made sure the bolts threaded cleanly into the tabs:
Square body tailgate window motors

The electrical plugs are exactly the same, and both motors ground through the motor body.

Below, a comparison of the door window motor and the tailgate window motor. The door window motor is painted black while the tailgate motor is bare silver.

Square body tailgate window motors

             --Back to top--

Site design and copyright Tradecraft Specialties, 2014 - 2023