Replacement Trailair Flex Air 5th Wheel Pin Box for Lippert 1621

Question:

I am wanting to replace current 1621 pin box with a Flex Air pin box. It appears the direct replacement is a L05 328492 with long jaw. One thing to mention is my truck has 8foot bed. According to Lippert customer service they said to use the M15 328484 medium jaw which would replace the 0719 OEM. I looked at measurements and feel like the medium jaw would bring unit awfully close to tailgate. Is there an issue with going with the L05 even though I have a long bed truck?

asked by: Gary

Expert Reply:

No, the Lippert 1621 will not have any issues with an 8' truck bed. The trailer will just sit a little further back. I spoke to my contact at Lippert and they stated that the general rule of thumb for a truck with an 8' bed would be to use a short/medium pin box. However, this could in turn create an interference issue with the tailgate as you mentioned. It will also put more stress on the trailer's chassis. Therefore, I recommend replacing the Lippert 1621 pin box that came on your trailer with the the same style which is the Trailair Flex Air 5th Wheel Pin Box part # LC328492 for 18,000 lbs or part # LC369535 for 21,000 lbs.

I have attached a review video of the above pin box for you as well.

expert reply by: Conner L