What Flex Air Pin Box Will Fit A 2024 CrossRoads Redwood 4001LK?
Updated 01/19/2026 | Published 08/03/2024
Question:
Which flex air hitch will fit my 2024 redwood 4001lk?
asked by: Steve S
Expert Reply:
Hey Steve, I can definitely point you in the right direction. In order to determine the correct replacement pin box for your camper, I will need to know the size or pin box number of the current pin box. There is no way to look up your 5th wheel to know exactly what pin box size it was equipped with from the factory. There should be a tag or sticker on the pin box that shows the brand, model number and serial number and stuff. Sometimes this sticker will tell us the pin box size, or we can use the model number and serial number to determine the size.
If no sticker is present, we have a measuring guide that you can use to determine the pin box size. You will find a link to the guide below. Basically, you will measure the bolt hole spacing then reference your measurements to a chart and it will tell you the size.
For example, the Curt Flex Air 5th Wheel Pin Box # LC369535 will replace the Lippert 1621 pin box. The 1621 is very common so this very well may be what you have, but please do confirm this.
If you can tell me your pin box size, I am happy to look into it and see what we have for you. Or if you don't know the size you can email me a picture of the pin box sticker and I can take it from there. My email is [email protected].
Product Page this Question was Asked From
Curt Flex Air 5th Wheel Pin Box - Lippert 1621 - 21,000 lbs
- 5th Wheel Pin Box
- Upgraded Pin Box
- Absorbs Road Shock and Reduces Chucking
- 21000 lbs
- Air Ride Suspension
- Fixed Turret
- Lippert 1621
- CURT
more information >
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Jesse M.
1/19/2026
Hey Steve, were you able to find the pin box number or take the measurements for your Redwood 4001LK? Once you had that info, did the Flex Air hitch end up being the right fit? Your update could make it easier for others trying to match their pin box.