What Gooseneck Pin Box do I Need for My 2025 Coachman Brookstone 374RK with 18" Clearance?

Updated 04/25/2025 | Published 04/18/2025

Products Featured in This Question

Reese Goose Box 5th-Wheel-to-Gooseneck Air Ride Coupler Adapter - 22,500 lbs

(324)

$2050.19

4" Offset Ball for B&W Turnoverball Gooseneck Trailer Hitches

(337)

$167.28

Reese Safety Chain Kit with Clevis Hooks - 44" Long - 20,000 lbs - Qty 2

(123)

$85.41

Question:

I have a 2025 Coachman Brookstone 374RK with the Rhino mount. I am wanting to replace fifth wheel pin box with a gooseneck pin box. The Gen-Y for the Rhino mount is too short with a front hole to center ball measurement of almost 14 inches. I need the measurement to be in the 16 to 18 inch measurement. I have a regular rear bed on my 2024 Chevy 3500HD SRW truck without the Puck system. I have a BandW turn over ball in my bed. What Gooseneck pin boxes fit this measurement that will bolt up to my Rhino box mount.

asked by: Keith N

Expert Reply:

Hello Keith,

Wow, that is a really nice 5th wheel, congrats!!

The Reese Goose Box # RP59KR is a great choice for replacing the factory Rhino-mount pin box on your 2025 Coachman Brookstone 374RK, particularly because of your need for a front bolt hole to center ball measurement between 16 and 18 inches.

The Gen-Y gooseneck pin box designed for the Rhino mount, while heavy-duty, only offers about 14 inches from the front mounting hole to the center of the gooseneck ball. That falls short of your requirement and can lead to clearance problems, including a reduced turning radius or even potential contact between the trailer and your truck cab.

In contrast, the Reese # RP59KR offers a measurement of approximately 18 inches (please refer to image I attached), which fits perfectly within your desired range. This added length helps ensure better cab clearance and makes the setup more compatible with your 2024 Chevy 3500HD SRW, which has a standard 6.75-foot bed and a B&W Turnoverball gooseneck hitch.

It’s important to note that although the Reese Goose Box is rated for 22,500 lbs, when installed on a Lippert Rhino frame, its maximum tow rating is reduced to 20,000 lbs. This is due to limitations in the Rhino bolt pattern and overall mounting design. However, this reduced capacity should still be well within the towing requirements for your fifth wheel.

One limitation of the Reese unit is that it has only one fixed mounting position on the Rhino frame, meaning you won’t have much vertical adjustment flexibility. Still, it’s likely the better fit compared to the Gen-Y because of its longer front-to-ball measurement, which directly addresses your clearance concerns.

The Reese Goose Box does not include safety chains, so you’ll need to purchase a set of the # RP49151.

One last thing, since you have a standard size bed you might want to get a 4" Offset Ball for B&W Turnoverball Gooseneck Trailer Hitches # BWGNXA4085 to help with turning radius.

Getting things geared up for a big upcoming trip? If so, where are you headed?