Installing Curt PowerHaul Custom Underbed OEM-Style Gooseneck Trailer Hitch on 2021 Chevrolet 2500

Updated 04/02/2026 | Published 03/29/2026

Products Featured in This Question

Curt PowerHaul Double Lock Custom Underbed OEM-Style Gooseneck Trailer Hitch - 38,000 lbs

$748.95

Question:

There are small rectangle steel pieces that I presume go inside the frame on driver and passenger side. There is a carriage bolt that goes through this steel piece for a washer then outside brackets to mount on with a 5/8 nut to top it. These would be towards the front towards front of vehicle of the hitch on both sides. I can not get the piece/bolt inside of the frame on either side. Im not sure how to mount those bolts. Mounting on 2021 Chevrolet 2500 standard bed, crew cab, work truckinch model.

asked by: Domonic E

Expert Reply:

Hey Domonic,

No worries, we have some tips and tricks that will help. You’re dealing with fishwire and the spacers. This is the part of the install that trips up almost everyone the first time.

First, you want to find an access hole in the frame.
Look along the side or bottom of the frame rail, there’s usually a bigger oval or round hole somewhere nearby.

Once you find that, grab your fish wire and thread it onto the carriage bolt. Just screw the coiled end of the wire onto the bolt threads.

Now, take that fish wire and feed it into the mounting hole.
Usually, you’ll push it through the hitch mounting hole first and out the access hole but sometimes you have to go the other way depending on space.

When the wire comes out the access hole, slide the spacer block onto the wire. After that, thread the carriage bolt onto the wire.

Now pull the fish wire back through the frame. That’ll pull the spacer block and bolt into position inside the frame, and the bolt should drop down through the mounting hole.

Once it’s through, leave the fish wire on while you start the nut.
That keeps the bolt from falling back inside the frame and saves you a ton of frustration.

What are you hauling with your Silverado 2500?