What is the Best 5th-Wheel Hitch for My 2021 GMC Sierra Short Bed without OEM Prep?

Expert Reply:

By far, the best 5th-wheel hitch for your 2021 GMC Sierra 3500 (6-1/2 ft. bed without factory prep package) is the Demco Hijacker # DM8550035 (21K) and the # DM8550034 (18K). These options are if you want to use above-bed adapters. If you wish to install below-bed adapters, you will need the # DM8550037 (21K) or the # DM8550022 (18K). The great feature about the Hijacker is that it automatically slides when your trailer makes sharp turns without the need to get out of your truck to make manual adjustments. The hitch also comes with 3 different height settings to customize the leveling needs of your trailer.

With the Hijacker, there are two different rail options for your truck: the underbed rail installation kit # DR37FR or the above rail installation kit # DM39FR. Both of these options require about 4 hours of installation time.

For fifth-wheel wiring, you will need the Curt 5th Wheel/Gooseneck Custom Wiring Harness w/ 7-Pole Connector - 7' Long # C56070.