1. Fifth Wheel King Pin
  2. Lippert Components
  3. 1621
  4. Lippert
  5. Reduces Bounce and Jarring
  6. 18000 lbs GTW
Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs

Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs

Item # LC328492
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Fifth Wheel King Pin
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Shipping Weight: 232 lbs
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LC328492 - Cushioned Lippert Components Fifth Wheel King Pin
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Flex Air drastically reduces chucking, absorbs road shock, and minimizes bounce. The internal air bag and built-in strut work with the rubberized pivoting head to achieve a dramatically smoother ride. Replaces Lippert 1621 pin boxes. Call 800-298-8924 to order Lippert Components fifth wheel king pin part number LC328492 or order online at etrailer.com. Free expert support on all Lippert Components products. Guaranteed Lowest Price and Fastest Shipping for Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs. Fifth Wheel King Pin reviews from real customers.
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  • Reviews (43)
  • Q & A (269)
  • Videos (2)
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Lippert Components Fifth Wheel King Pin - LC328492

  • 1621
  • Lippert
  • Reduces Bounce and Jarring
  • Lippert Components
  • 18000 lbs GTW
  • Pin Box Upgrade
  • Cushioned
  • Fixed Turret

Flex Air drastically reduces chucking, absorbs road shock, and minimizes bounce. The internal air bag and built-in strut work with the rubberized pivoting head to achieve a dramatically smoother ride. Replaces Lippert 1621 pin boxes.


Features:

  • Air ride pin box with a pivoting head replaces standard pin box on your 5th-wheel trailer to cushion your ride, improve handling, and limit strain on truck and trailer
    • Drastically reduces chucking
    • Virtually eliminates bounce and jarring
  • Internal air bag absorbs road shock
    • Scissor-like motion allows pin box to compress, compensating for jarring and bounce
    • Built-in shock ensures that pin box rebounds - keeps air bag from breaking down
  • Pivoting head limits chucking by allowing controlled movement of the king pin within your hitch
  • Rubber compound built into the head absorbs road shock
    • Reduces wear and tear on trailer
  • Black powder coat provides rust resistance
  • Sturdy steel construction
  • King pin connects to any 5th-wheel trailer hitch
  • Bolt-on installation with no assembly required
  • Made in the USA


Specs:

  • Designed to replace Lippert 1621 5th-wheel pin box
  • Weight capacity: 18,000 lbs
  • 1-Year limited warranty


Notes:

  • Do not use the Trailair Flex Air pin box with any type of gooseneck adapter.
  • Because of the size of this item, it ships via truck freight.

Getting there is half the fun, right? Not if you're being bumped, jerked, jammed, and pushed around from the chucking, road shock, and bounce that occurs as you tow your fifth-wheel trailer or RV. And imagine the costly wear and tear on your trailer as it endures that rocky ride.


Put the fun back into your trip and ease the stress on your trailer by replacing your factory pin box with the Trailair Flex Air pin box. The internal air bag and built-in shock work together to cushion your ride, improve handling, and limit strain on both your truck and your trailer. But what sets the Flex Air apart from other air ride pin boxes is the addition of a pivoting head. This head, along with its built-in rubber compound, provides additional cushion, absorbs road shock, and reduces chucking for a significantly improved ride.


Rubber Compound and Internal Air Bag Absorb Road Shock

Lippert Flex Air pin box has a rubberized pivoting head

A heavy-duty rubber compound is built into the head assembly of the Flex Air pin box. This rubber is the first defense against road shock. It helps to absorb the bumps and vibrations experienced when towing a fifth-wheel trailer over rough roads. Standard pin boxes without any type of shock absorption transfer road shock to your trailer, resulting in potential damage to the trailer and an overall bumpy ride. The shock-absorbing rubber inside the Flex Air takes the beating so there's less wear and tear on your trailer or RV and you get a smoother ride.


Lippert Flex Air pin box has a shock and air bag

Because the rubber may not be able to absorb all of the road shock that you experience, the Flex Air also implements air ride technology to virtually eliminate shock. When you encounter uneven terrain on your trip or hit a pothole on the highway, the Flex Air pin box compresses vertically, similar to how a pair of scissor blades closes in on each other. This compression transfers the road shock and vibrations to the internal air bag, saving your fifth-wheel hitch, trailer, and tow vehicle frame from enduring a rocky ride.


A built-in strut, or shock, controls the Flex Air's compression so that the internal air bag doesn't burst. The strut also causes the pin box to appropriately rebound without any bounce, and positions it to be ready for the next bump in the road.


Pivoting Head Reduces Chucking

Lippert Flex Air pin box has a pivoting head that reduces chucking

The pivoting head on Flex Air allows for controlled back and forth movement of the king pin to reduce the uncomfortable jarring known as chucking. Unlike a rigid pin box that has little give at the point where the trailer and the hitch are connected, the Flex Air can pivot slightly to compensate for those times that your trailer suddenly pushes or pulls on your tow vehicle. Because the pin box head - not the king pin itself - is moving, the chucking that often occurs when the king pin jerks around inside the hitch is significantly reduced.


Simple Setup and Installation

First, simply remove your existing Lippert 1621 pin box from your trailer. The Flex Air uses the same bolts that held on your original pin box so no additional hardware is required for installation. Plus, the Flex Air pin box comes out of the box ready to be put on your trailer, so no assembly is needed. Because the Flex Air is quite heavy, you should put it on an elevated surface or have a friend help you support its weight during installation.


The internal air bag should be inflated after the Flex Air pin box has been mounted on your trailer. Using the air intake valve, inflate the air bag until the outer cylinder of the shock rises high enough to fully expose the yellow inflation indicator sticker.



328492 Lippert Components (LCI) Flexair by Trail Air Fifth Wheel Kingpin Box for Lippert 1621

Installation Details LC328492 Installation instructions



Video of Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Lippert Trailair Flex Air 5th Wheel Pin Box Manufacturer Demo

Many people love the spacious luxury of Fifth Wheel RVs but don't love the tugging, jostling and chucking the comes with towing. Towing can be an exhausting experience and RVs can really take a lot of abuse from bumpy roads. Protect your RV and improve you towing experience by upgrading the the Flex Air Pin Box by Lippert Components. The Flex Air Pin Box combines our time-tested trail-air air-ride technology with our rota-flex pivoting head to create an unparalleled ride. Eliminating chucking and the vertical tug-of-war between the Fifth Wheel and tow vehicle. The Flex Air Pin Box utilizes an air bag as a buffer between the tow vehicle and Fifth Wheel RV to absorb road shock and vibrations. It's integrated oil shock absorber handles rebound action, dampening kick-back and controlling chucking. The Flex Air Pin Box also features a pivoting head in its lower jaw that controls the vertical tug-of-war between the two vehicle and Fifth Wheel RV and its rubberized compound provides an additional buffer to help protect the Fifth Wheel RV from jarring motion.

Air ride suspension has been standard on most tractor trailers for years and we want Fifth Wheel RV owners to enjoy the same benefits. Upgrade today and enjoy the comfort of air with a Flex Air Pin Box by Lippert Components. .


Customer Reviews

Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs - LC328492

Average Customer Rating:  4.5 out of 5 stars   (43 Customer Reviews)

Flex Air drastically reduces chucking, absorbs road shock, and minimizes bounce. The internal air bag and built-in strut work with the rubberized pivoting head to achieve a dramatically smoother ride. Replaces Lippert 1621 pin boxes.

- LC328492
by:

Very happy with the hitch. Makes the towing easier and less stressful. 427818



- LC328492
by:

Install went pretty smooth. Did it from the bed of the truck, using a motorcycle jack in front and a small hydraulic in back. Make sure your torque wrench can dial to 160 ftlbs. I will update after I tow it!!! 602475


Comments
I cannot believe it has been a year....and a trip to Perdido Key, FL and Breckenrigde CO. In addition to taking care of us, I have to tell you, it will take care of your trailer too! Improved our towing experience old pin box was an upgrade Rotoflex greatly. Worth every penny! If you did not see my earlier post, my friend and I installed it ourselves. Motorcycle jack in the back of a pick up bed. :
James J - 02/05/2020

65292

- LC328492
by:

Love the pin box, suggest it to all 388409



- LC328492
by:

The Flex Air does exactly what I wanted it to do. It absorbs the shock of bumps and transfers that energy to the hitch, not the truck or the fifth wheel. Installation was straight forward with a little bit of planning. It did require I adjust the fifth wheel hitch in my truck as this is a little longer than the original and extends downward more. I was able to modify the settings on my hitch to accommodate. Overall, I've happy I added this to my RV. 375017



- LC328492
by:

Having not pulled a fifth wheel with a traditional pin box setup I have nothing to compare it to. Watching the suspension action over various road conditions I would have to assume that it is doing a very good job of stopping the transfer to the trailer. We have found that we have to keep an eye on the air pressure because it seems to lose air over time (months). We keep a portable air pump in the trailer to cover this situation. The only other observation I have is that the design does seem to carry the nose of the trailer a bit higher. My truck has had no suspension adjustments made to it and the hitch-head is set at it's lowest setting. I can't blame the pinbox alone because there are many contributing factors, but an element of consideration none-the-less. All in all it's a sturdy, well built, piece of hardware that adds a third layer of suspension to the traveling experience. The health of the trailer will definitely benefit from its use. I have had multiple comments made by other campers. 333916



- LC328492
by:

This is some of the best money we ever spent. It truly makes a huge difference in the ride - even on the roughest roads and bridges. Wouldn't pull a long trailer without it now. The handling is so much better - the trailer doesn't try to 'drive' the truck for you. If you want a better, smoother ride - this is what you need. No more bucking felt. Install was very easy. Highly recommend this product - you won't be disappointed. 351642



- LC328492
by:

I will be on the third flexair pin box when it gets here on the 21st of November 2016. The problem iIm having is with the lower roto flex portion. The rubber block shifts and I have talked to others with the same problem. Lippert has been great about the replacement, But the the hassle of replacing this three times in one year is not worth it. 318083



- LC328492
by:

Good morning, The reason for buying this item was to controled the tugging, jostling and chucking of our RV. Im not disappointed with the result ,it works very good and doing that will prevent wear and tear of the RV. The installation is very easy. All in all very satisfied. Service was also excellent.. Thanks 529925



- LC328492
by:

The product that I ordered was what I received the person I talked to was very noligable and helpful Thanks 572652



- LC328492
by:

What a difference this pin box made in towing my fifth wheel. Excellent product, makes towing a joy! Took the bumps and jerking out of towing. Went to 12 states and 14 National Parks up mountains and down back roads after installing this pin box. Put on over 12,000 Miles. It’s worth every penny I paid for it. Will never own a fifth wheel with out one. Thank you for making this wonderful product! 501084



- LC328492
by:

I am very happy with my Flex Air king pin. The customer service folks worked with me so I could have it before going on vacation. The old one came off and the new one fit right up. I used a forklift to do the lifting. it sure made the trip to DC more enjoyable. 292954



- LC328492
by:

I have used my Flex Air for over one year and put around 3000 miles on it. I purchased this for one reason to reduce bucking when I it bumps in the road. I can safely say that it has virtually eliminated the bucking. It has also made the ride a lot smoother. I would highly recommend the Flex air. I did my own install of this product by my self. My rig 2018 Toyota Tundra with a Husky 16 KW Hitch 2017 KZ Durango 30 ft. 637982



- LC328492
by:

Great product. Did it stop all the chunking--NO but it helped take away half the beating we were getting from the 5th wheel. Worth the investment! 538610



- LC328492
by:

Gives better ride than my original pin box, but not worth the extra money. Also, due to the added length, I had to remove my fold up bed cover. Air bag needs inflation before each use. 324839



- LC328492
by:

Really helped take away most of the jerky ride we used to get from our solid king pin. The air bag helps to smooths out rough roads. As per the advice of Lippert customer service I made 5 pound adjustments until I found the best ride. I keep a portable battery operated air pump along for adjustments. My airbag had a small air leak at the valve threads when new. After resealing the threads all is good. 513070


Comments
Still working great. The smooth ride makes towing much more enjoyable.
Wesley - 05/28/2019

55786

- LC328492
by:

1st one had wrong bag(to small and would not lift trailer) they paid for all shipping etc for exchange. Hard to tell how well it works because I have bags also but overall I'm pleased. 312386


Comments
Mixed bag, it functions perfectly but I also have air bags on truck so it performance is improved by that. I had problems with not being able to fit air fill nozzle on filler, clearance issues. Rubber chucking damper pad got squished out backside of hitch requiring me to disassemble and install screws to hold rubber in place. And it just looks like a clap trap. Ive been looking at the Reese® Goose Box™ Gooseneck Coupler.But I also have the metal rollup tauno cover that causes clearance issue with both. So to sum it up, it works.
Tom - 11/01/2017

30246

- LC328492
by:

4 stars as I have just recently installed this although I received it over a year ago. I just put 750 miles on it and experienced almost every PAVED road condition imaginable and it worked great. I can't imagine what that would have been like with the stock pin box. 4 stars because I still need to see how it performs off road and I am just a few days into using it on a trip covering OR, ID, MT and WY so I still have my personal evaluation to complete and need more drive time to see if anything fails on it. Installation was a breeze but it's a heavy hitch so caution is advised. 572537


Comments
I just finished a 3,000 mile trip from Oregon to South Dakota. The hitch works like a dream. Very few road issues are transferred to my truck from the trailer. This is a great hitch. Totally satisfied with this purchase.If anything I wish they made an offset pin box so that I could adjust it to make my trailer ride correctly, as it is with my 4x4 it runs a tad nose high.
Arman K - 10/08/2019

62736

- LC328492
by:

Installed flex air myself with 2 friends used a floor jack on the bed of the truck to raise the flex air ,went right in .the flex air works great you can see it flex going down the road .the ride is very smooth. Remember to air it up before you connect each time mine takes about 105psi but I have a heavy 5th wheel toyhauler .well worth the money a lot less than campingworld and other places. With the flex air your truck and 5th wheel each will ride so much smoother and less stress on both vehicles. 5 stars from me . 552548



- LC328492
by:

First, about etrailer. As always, their service was outstanding. They honored their low price guarantee without question and shipping was fast. I upgraded from a Trailair Air Ride pin box with a fixed turret. That pin box helped with bouncing and jarring, but I still got a lot of "chucking". This FlexAir pin box solved that problem as well. Installation was a breeze, although you must make sure you have enough adjustment on your trailer to mount this pin box higher up than your existing pin box. I had to mount it at the very highest set of holes on my trailer. Lipperts web site has specs on this pin box and installation instructions, including measurements and torque specs. With the help of a friend and using the bed of my pickup truck, we unbolted the old one and bolted the new one in. Took about an hour and that was not hurrying. I took the trailer out this past weekend with the new pin box and hit some pretty bad roads. Wow! What a difference this pin box makes. I can only describe the ride one way. Smooooooth. I am very pleased with both etrailer and this product. It's pricey, but to me, pulling a large fifth wheel trailer, it's worth every penny. Highly recommended. 287066



- LC328492
by:

I bought the Flex Air to replace the standard Lippert pin box on our Cedar Creek fifth wheel that weighs 12K lbs. Just looking for something to smooth out the ride and the Flex Air seemed to have good reviews and recommendations. I went to the Lippert website to download the installation instructions because I couldn't get the link on the etrailer website to work. The instructions will give you the torque values required for installation and the air pressure for the inflatable airbag on the hitch. Installation was straight forward, but you better have a plan because this thing is heavy (300 lbs) and it will take some manpower to move around and install. 749960



- LC328492
by:

This is the best money I have spent on my camper hands down. My hitch weight is a bit over 3200 lbs. I use a PullRite Super Lite hitch, photo attached. Once locked on the king pin, four bolts are set from the adapter plate against the king pin plate. The plate on the Flex Air is twice as thick as the original pin box and I have way more confidence in a solid set of these four bolts. I was blown away by how this hitch absorbed road shock. I will never have another 5th wheel without this set up. 749458



- LC328492
by:

Pin box was just as I ordered. It does improve the ride. Won't make your truck ride like a Cadillac but does help. I was also surprised that it was shipped in a card board box that was coming apart when it got to me. A wooden crate I think would be better. 725583



- LC328492
by:

This is our second Flex Air. It really smooths out the ride for the 5th wheel on wavy or bumpy roads. 722990



- LC328492
by:

This 250 lb item was shipped in a cardboard box that was just sitting on a pallet. When I opened the box I found the Flex Air was sitting upside down with the foam pad on top. I have no idea how the air filling nozzle wasn't damaged. Luck I guess. There were no "UP" markings on the box. No instructions were included. Installation went smooth, it's just heavy so be careful. Instructions and videos can be found on-line. The Flex Air is at least 4" taller than the OEM box that came with our Grand Design Reflection. I mounted the Flex Air as high as I could and lowered the receiver on the truck. The trailer is still nose high but seems to tow fine. My test ride was noticeably smoother. You can see a lot of motion on the Flex Air that would have otherwise been transferred to the truck. 722359



- LC328492
by:

Great product! Took 80% of the bucking out of the ride.It was an easy install and very happy with the results. Just came back from a 4,000 mile test drive and all is good. 706049


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Ask the Experts about this Lippert Components Fifth Wheel King Pin

  • Benefit of Using 5th Wheel Pin Box Rated for More Than Trailer Actual Weight
    The Lippert TrailAir Flex Air 5th Wheel Pin Boxes # LC328492 and # LC369535 are both bolt-on replacements for the model 1621 OEM pin box. Their difference, as you noted, is in their rated weight capacities; 18K for # LC328492 and 21K for # LC369535. Either one will be fine for use with a compatible trailer with a GVWR of 16,500-lbs. But yes, safety margin in the form of extra capacity is a good thing. The relatively low incremental cost for the 21K pin box over the 18K makes a pretty...
    view full answer...
  • How to Determine Fifth Wheel Pin Box Model
    If you are unable to contact your trailer's manufacturer with your VIN to find the factory pin box model number there are some steps you can take which will allow you to determine what pin box model you have so you can purchase a new FlexAir. To do this you will need to follow the steps in the linked help article, which I will go over with you. Start by selecting your pin box style like in the accompanying photo (which you will also find in the help article). You will then need to use...
    view full answer...
  • Should Pin Box or Suspension be Upgraded to Reduce Jarring and Bouncing While Towing
    A cushioned pin box, like the Trailair Flex Air 5th Wheel Pin Box # LC328492 for a Lippert 1621 replacement that you referenced, will greatly improve the ride between your 2016 Ram 3500 and your Forest River Chaparral 37FL whereas upgraded suspension parts on your trailer are geared more towards the ride quality of your trailer. If the jarring that you are getting is from the trailer bouncing around then I recommend starting with suspension enhancement. From the info you gave it sounds...
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  • Replacement Trailair Flex Air 5th Wheel Pin Box for Lippert 1621
    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...
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  • Replacement Pin Box for a 2012 Jayco Eagle 5th Wheel Trailer
    I spoke to my contact at Lippert and they informed that they did not start keeping a record of pin boxes until 2013. Therefore, the only way you are going to be able to identify what bolt pattern you have is by measuring the mounting holes using the attached photo. The most common bolt pattern is a 1621 which measures as follows: 2a: 7-7/8" 2b: 2" 2c: N/A 2d: 5/8" 2e: 15/16" 2f: 6 3a: 17-3/4" 3b: 25-5/8" 3c: 12" If your measurements match these then the correct Trailair Flex...
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  • How To Choose Pin Box Replacement Without a Sticker On Pin Box
    Since trailer manufacturers do not make information like pin box models readily available to the public, you will need to contact the dealership with the serial number and they should be able to tell you what pin box is on it. Otherwise, the only other way besides a sticker is taking a few measurements. I have attached an article explaining how to measure your pin box to figure out which replacement is suitable.
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  • Can Trailair Flex Air # LC328492 Replace Lippert 1621HD Pin Box on a 2017 Jayco Seismic Wave 355W
    You are on the right track of choosing an upgrade for the Lippert pin box on your 2017 Jayco Seismic Wave 355W. Since the pin box is a 1621HD instead of a regular 1621 you need to go with a different pin box as the Trailair Flex Air # LC328492 is only compatible as a 1621 replacement. If you like the Trailair line then you can use the Trailair Air Ride # LC158778. This is rated for 21,000 lbs and the only difference between this and the Flex Air is that the Flex Air has a pivoting head...
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  • Are Replacement Parts Available for the Trailair Air Ride 5th Wheel Pin Boxes
    The reason that you cannot find the replacement shaft is because Lippert does not offer this separately. If the shaft is worn or damaged then it is time to replace the pin box. There are only very minimal replacement parts for these pin boxes (valve part # LC156740, shock part # LC177223, airbag part # LC432404) and this is intentional to discourage home repairs on such a critical component. That said, this might be a good to time to upgrade from the Trailair Air Ride 5th Wheel Pin...
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  • Sidewinder Pin Box Recommendation for 2018 Grand Design Momentum 351M For Short Bed Turn Clearance
    Since your 2018 Grand Design Momentum has a Lippert 1621 pin box the Trailair Flexair part # LC328492 will fit and give you a much smoother ride but will not make a noticeable difference in clearance between truck cab and trailer. A better option for that would be the 5th Airborne Sidewinder part # RP61422 which fits the Lippert 1621, is also cushioned, but moves the pivot point back 22.5 inches so that you can tow your trailer with your short bed truck and fixed hitch. Only other way...
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  • Correct Trailair Flex Air 5th Wheel Pin Box for a Heartland Bighorn 3010RE
    The Trailair Flex Air 5th Wheel Pin Box part # LC328492 is compatible with a Heartland Bighorn 3010RE and will work with a PullRite SuperGlide 5th Wheel Trailer Hitch. However, you will need to obtain a Quick Connect Capture Plate from PullRite. This capture plate is to ensure the Flex Air does not pivot inside the jaws on the SuperGlide.
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  • Replacement Trailair Pin Box for MOR/ryde RPB72-1716 Pin Box on Trailer
    Based on my research, your MOR/ryde RPB72-1716 pin box would have replaced the factory Lippert 1716 pin box on your trailer. The Trailair Flex Air 5th Wheel Pin Box # LC328492 that you referenced is designed to replace the Lippert 1621 pin box, so it will not work on your Arctic Fox trailer. The closest pin box upgrade we have available to the Trailair Flex Air that will work on your trailer is the Trailair Air Ride # LC158777, which is designed to replace the Lippert 1716 pin box. This...
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  • Air Ride Pin Box and Locking Plate for Lippert 1621 Pin Box and HiJacker 5th Wheel Hitch
    To replace your Lippert 1621 pin box I recommend the 5th Airborne pin box # 5AB-E1621-610. There aren't a lot of options for locking plates for the various air ride pin boxes so this is your best option. The locking plate you would use with it and your Hijacker is # DM6062.
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  • Will Husky Lube Plate Fit King Pin on Trailair Flex Air 5th Wheel Pin Box
    The Trailair Flex Air 5th Wheel Pin Box # LC328492, which replaces a Lippert 1621 pin box, has a standard 2" king pin. The Husky Lube Plate # HT34914 will still fit though as the 2-7/8" diameter referenced is talking about the upper "lip" area right under the pin box (see attached). These 2 pieces will work great with a Curt 20K 5th wheel hitch.
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  • Recommended Replacement Pin Box for Lippert 182209 1621 on 2010 KZ Durango LX
    I reached out to my contact at Lippert and you do have the 1621 pin box on your 2010 KZ Durango LX. If you are looking for a cushioned pin box, I recommend the Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs # LC328492 or the 21,000 lb # LC369535. Either of these will work well and they not only have the air ride but also have a rubber compound and moving head to be the fist defense against road shock and chucking. If you desire greater turning clearance, then the 5th...
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  • Flex Air Replacement Shock Availability
    It's hard to see the dent in the picture you submitted so it's harder to say but it looks like it's probably fine. I'd probably take it on a short trip around the block keeping and eye on it and see if it works like it should. If you find you need a replacement you'd want the part # LC177223.
    view full answer...
  • Compatibility of TrailAir Flex Air # 328492 with Pull Rite ISR Hitch
    I reached out to my contact at Lippert and confirmed the Trailair Flex Air 5th Wheel Pin Box # LC328492 will work with the king pin adapter that comes with your ISR Series SuperLite 4 Point PullRite hitch. This will replace your MorRyde pin box to give you the air bag for a smoother ride. There will not need to be any adjustments to the hitch to make this pin box compatible.
    view full answer...
  • Is the TrailAir Flex Air 5th Wheel Pin Box Compatible With The PullRite 2400 20K Hitch?
    The Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs, # LC328492, is compatible with all 5th Wheel Hitches but not any Gooseneck hitch adapters. It will work with the PullRite hitch you mentioned. All you need is the correct capture plate but you can get that from Pullrite. It should be part number PR_331756 or PR_331760.
    view full answer...
  • How to Pick Out Cushioned Pin Box for Open Range Light Camper
    First we have to determine what pin box you have on your Open Range Light camper so that we can pick out a cushioned pin box. I am fairly certain you have either a Lippert 1621 or a 1716 but I wasn't able to narrow it down beyond that. What you need to do is check out the pin box looking for a sticker or plate that has either of those numbers listed. If you have a 1621 you would want the # LC328492 or if you have the 1716 you would want the part # LC158777. Both of these are cushioned...
    view full answer...
  • How To Determine If a 5th Wheel Trailer Needs to Be Raised or Lowered To Tow Level
    It sounds like you are trying to determine if the trailer will be level while coupled to the tow vehicle. If that is the case then what you need to do is measure the distance from the ground to the bottom of the skid plate on the pin box and then from the ground to the top of the skid plate on the 5th wheel hitch. The height of the hitch and skid plate are both adjustable so you may need to tweak these as well. I would try to get these two as close to level as you can but keep in mind you...
    view full answer...
  • Flex Air Pin Box Recommendation for 2013 Winnebago 30FWRES with Lippert 1621
    Since your serial number starts with 028 you do have a Lippert 1621 pin box. The Flex Air part # LC328492 would be the best option as it offers two forms of cushioning. This will work well and is actually made by Lippert too so it was designed specifically for your trailer basically.
    view full answer...
  • Air Ride Pin Box to Replace a Lippert 1621HD Pin Box on Cedar Creek Silverback 5th Wheel
    The 1621HD is the number that I need. That means it is a Lippert 1621HD pin box. Since you will want to make sure to get a match for the 1621HD and not just the 1621 the one option is a 5th Airborne pin box, # 5AB-E1621-610. It also has an air bag and a shock inside, it is just designed differently than the Trailair models. I have linked a video showing installation for you.
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  • Distance From Front Bolt Holes to King Pin on Trailair Flex Air # LC328492
    The Trailair Air Ride 5th Wheel Pin Box # LC328492 that you referenced, which is confirmed to work with the Lippert 1621 pin box on your trailer, features a distance of 21-1/2 inches from the center of the front row of bolts to the center of the king pin. I have attached an image to assist. This replacement pin box will do a great job of reducing chucking and absorbing road shock with its internal air bag and built-in strut. I have attached a short video demonstration on this product...
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  • How to Pick Out a Trailair Pin Box for a Primetime Crusader 315RST
    You will need to determine which pin box you have on your trailer before you can pick out the correct Trailair pin box. The part # LC328492 fits the Lippert 1621 pin box which is very popular and is most likely on your trailer but you need to verify this first. Up near the pin box there will be a plate or sticker that has the pin box info listed. If you do not have a 1621 check out the link I attached that has all of the pin boxes we offer. You will need to select your pin box from the...
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  • Correct Trailair Replacement for Lippert 1621 Pin Box
    I spoke with a representative of Lippert who told me that you have a Lippert 1621 pin box with a 15,500 lbs capacity. For a Trailair you could use Trailair Flex Air 5th Wheel Pin Box # LC328492. These pin boxes are going to substantially reduce the amount of jarring and chucking you experience by absorbing the road shock with an air bag. It is a simple bolt-on design and has a capacity of 18,000 lbs, though Trailair # LC369535 would also work for you and has a capacity of 21,000 lbs....
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  • Which Trailair Pin Box will Replace a Dexter 221-0033-00
    We have a Trailair Pin Box that will fit as a replacement for your Dexter Turret 221-0033-00 but not a Flex Air. For that you would want the part # UF35-946231.
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  • Comparing Lippert Components Trailair Pin Box To Trailair Flexair Pin Box
    The Trailair Air Ride 5th Wheel Pin Box - Lippert 1621 & 1621HD - 21,000 lbs # LC158778 and the Trailair Flexair 18,000 lb # LC328492 are more similar than different. The major difference that you stated is the capacity and the second notable difference is the Flexair 18K has a rubber compound built into the head assembly as the first defense against road shock. If your trailer's GVWR is under 18,000 lbs, I recommend the Trailair Flexair 18K # LC328492 due to the extra layer of shock...
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  • Air Ride Pin Box for an 18,000 Pound 5th Wheel Trailer with Lippert 1621HD Pin Box
    For an air ride pin box that will fit in place of your 18K rated Lippert 1621HD pin box you have a couple of options. You can use the 5th Airborne unit # 5AB-E1621-610. I have linked a video showing an example installation for you. You could also use the 21K rated FlexAir pin box, # LC328492. Both of the above pin boxes feature both an air bag and a shock to reduce chucking and provide an overall better towing experience. But if I was choosing one I would go with the new FlexAir....
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  • Trailair Flex Air Pin Box Compatibility With Demco Hijacker Autoslide 5th Wheel Hitch
    The Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs # LC328492 is compatible with the Demco 18K Hijacker Autoslide 5th wheel hitch like # DM8550034 when you use the Demco Hijacker Autoslide Capture Plates for Trailair Rota-Flex Pin Boxes # DM6171. I've attached a video to assist. If you have the factory prep package, you will also want to use the rail adapter # DM6194. That combination will give you a really nice ride and driving experience with your short bed truck....
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  • Replacement Pin Box Recommendation For Lippert 1116
    The Trailair Flex Air 5th Wheel Pin Box, part # LC328492, is designed to replace the 1621 pin box, but is not designed to replace the Lippert 1116. The replacement pin box we offer that is a direct replacement for the Lippert 1116 is the Ultra-Fab Trailair Air Ride 5th Wheel Pin Box, part # LC155943. This pin box reduces the jarring and chucking, and has an internal air bag that cuts down on bouncing from road shock. I have attached a product review video for this pin box you can check...
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  • Difference Between Long and Medium Pin Box Style When Selecting Replacement
    Trailair Flex Air 5th Wheel Pin Boxes, such as the Lippert # LC328492, are designed to replace the existing pin box on your trailer. The long and short jaw models that you referenced in your question simply refer to the type of pin box that the unit is designed to replace. In order to find the correct replacement king pin, you will want to determine what you have on your trailer. The easiest way to do this is to simply look for the pin box number on your trailer, which should be located...
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Info for this part was:

Expert Research:
Mike L
Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
John H
Expert Research:
Adam R
Expert Research:
Jeffrey L
Written by:
Chelsea B
Updated by:
Shelly K
Updated by:
Sarah W
Updated by:
Hannah L
Updated by:
Isabelle B
Installed by:
Michael B

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