Troubleshooting Curt 5th Wheel Brackets And Rails That Aren't Lining Up During Installation

Updated 08/20/2021 | Published 08/19/2021

Question:

The kit says it’s for a Chevy/ gmc with a 6/6 box or an 8 ft box. My truck has the 6-6 box and I started by marking and drilling the six holes in the bed using the 47.500 dimension in the directions..... this does not align with the frame rail brackets... my question is why. And please provide a solution. At the present time my truck has holes in the box that don’t work.

asked by: Kelly F

Expert Reply:

The Curt Custom Fifth Wheel Installation Kit for Chevy/GMC # C16400-204 have custom brackets that will not work with any Denali models so if your 2015 GMC Sierra 1500 is a Denali then these brackets will not fit correctly and line up with the rails.

When measuring the 47.5" for the back rail did you measure from the tailgate side or the cab side? You'll need to measure from the tailgate side for a correct fit. You'll also want to ensure that the rails are equal distance on each side from the bed rails for the holes to line up correctly. Curt recommends using a 1/8" drill bit for the pilot holes to ensure you're lined up and then widening them to 9/16".

If this does not solve your issue please reply back and we can keep troubleshooting.

expert reply by: Kevin C