Determining Which Reese Goose Box 5th Wheel To Gooseneck Adapter Fits 2021 Keystone Cougar 316RLS

Question:

Hi there! I have a 2021 Ram 2500 short bed crew cab with the factory 5th/goose prep pkg. I also have a 2021 Cougar 316RLS 5th wheel being built, so I havent got the actual king pin it comes with, although I do have pics of it - off another one. I do want to go with the reese goosebox and need assistance so I can order it in time to replace the kingpin. I hear the king pin could be a lippert 1621 Also, do you think I need an offset ball? I seen another post about this but sometimes it gets confusing and I dont think I do you are the experts. I appreciate it

asked by: Robert B

Helpful Expert Reply:

I would be happy to help, though you will want to confirm the pin box that is being installed on your specific trailer before ordering a Reese Goosebox to make sure you get the correct one.

Assuming that your 2021 Keystone Cougar 316RLS 5th wheel trailer does have the Lippert 1621 pin box you mentioned the Reese Goose Box # RP85FR would be the correct replacement.

Since your 2021 Ram 2500 has the short bed and the OEM towing prep package I recommend going a different route as there is not an offset gooseneck ball that will work with your OEM gooseneck hitch due to it using ball bearings to secure it which allows the ball to rotate and would cause issues if the ball had an offset. While the # RP85FR may work with a standard gooseneck ball, you will likely not be able to make very sharp turns and could have accidental cab to trailer contact if you aren't careful.

Instead I recommend going with the Ranch Hitch Universal 5th-Wheel-to-Gooseneck Coupler Adapter w/8" Offset for Short-Bed Trucks # AM3139 as it has built in offset which will allow you to make sharper turns without having cab to trailer contact, but will require your pin box to be a standard non-cushioned model.

If you can let me know exactly which pin box your trailer uses I would be happy to confirm which options are available for you.

I included videos for each of the products mentioned for you to take a look at.