Replacing Lippert Rota-Flex with Reese Goose Box on 2018 Grand Design Solitude

Question:

2018 Grand Design Solitude ST377 MBS 20,000lb Gen 2 goosebox. What part number. Am towing with a 2003 Dodge Ram 2500 HD long bed. Red tag Firestone air bags. Using a Pop Up brand gooseneck hitch. Simply need to know which part number hitch to order. Currently using a Roto Flex with a Anderson Ultimate Hitch and want to change for this unit. Thanks for a reply

asked by: David B

Helpful Expert Reply:

To replace your existing Rota-Flex 5th wheel pin box with the Reese Goose Box 5th-Wheel-to-Gooseneck Air Ride Coupler Adapter # RP85FR, you'll need to confirm its model number and weight rating. This information is typically displayed on a sticker or plate on the pin box itself.

Lippert makes three models of the Rota-Flex, so the weight rating on the label is enough to identify which of these three you have:

-Model 1621/1621HD Trailair Rota-Flex 5th Wheel Pin Box 18,000 lbs # LC328330
-Model 1116 Trailair Rota-Flex 5th Wheel Pin Box 19,000 lbs # LC176440
-Model 1621 Trailair Rota-Flex 5th Wheel Pin Box 21,000 lbs # LC328329

The Reese Goose Box # RP85FR is designed to replace a Lippert 1621 pin box and is rated for 20,000 lbs, so it's a suitable replacement only if you have the # LC328330 Rota-Flex (18K).

There isn't a Goose Box designed to replace an 1116 pin box and if your Grand Design currently has the # LC328329 21K, it is not recommended to replace your pin box with a lower rated one, like the # RP85FR, which is the highest rated Goose Box available.