1. Accessories and Parts
  2. Reese
  3. Fifth Wheel King Pin
  4. Sidewinder Parts
  5. Leland Pin Box
Sidewinder Rotating Turret Premium Pin Box Coupler - ST400

Sidewinder Rotating Turret Premium Pin Box Coupler - ST400

Item # ST400
lowest price pledge
Our Price: $428.64
You Save: $389.89
Accessories and Parts
This item qualifies for Free Shipping
Shipping Weight: 76 lbs
ST400 - Sidewinder Parts Reese Accessories and Parts
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images


This Sidewinder rotating turret premium pin box coupler is designed to work with the Sidewinder standard or super duty arm. Call 800-298-8924 to order Reese accessories and parts part number ST400 or order online at etrailer.com. Free expert support on all Reese products. Guaranteed Lowest Price and Fastest Shipping for Sidewinder Rotating Turret Premium Pin Box Coupler - ST400. Accessories and Parts reviews from real customers.
  • All Info
  • Reviews (2)
  • Q & A (7)
  • Videos (1)
  • Photos
  • Why etrailer?

Reese Accessories and Parts - ST400

  • Fifth Wheel King Pin
  • Sidewinder Parts
  • Reese
  • Leland Pin Box

This Sidewinder rotating turret premium pin box coupler is designed to work with the Sidewinder standard or super duty arm.


  • Rotating turret style premium pin box coupler
  • Designed to work with the Sidewinder's standard or super duty arm
  • Fits OEM pin boxes
    • Leland: 7910, 7920, and 7921
    • Dexter: 221-00374
  • Made in the USA

ST400 Sidewinder Rotating Turret Premium Pin Box Coupler - ST400

California residents: click here

Video of Sidewinder Rotating Turret Premium Pin Box Coupler - ST400

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

Video Transcript for Reese Fifth Wheel King Pin ST400 Review

Speaker 1: Today we're going to take a look at the Reese sidewinder rotating turret premium pin box coupler. Now, this rotating turret style premium pin box coupler will replace the factory pin box on your Fifth Wheel. This part is designed to install onto the Reese Sidewinder Standard or Super Duty arm and allows the sidewinder rotate 90 degrees.The Reese sidewinder is designed specifically for short bed trucks. A nimble, quick design will automatically eliminate turning and clearance headaches and allows you to make up to 90 degree plus turns without exiting the truck. This part will include just the turret, the rotating turret with the wear bushing, the installation hardware and the wear disc to allow you to install this onto the sidewinder. It is designed to fit standard OEM pin boxes like the Leland 7910 and it fits extended OEM pin boxes like the Leland 7920 and 7921.

This part is made in the USA. The last thing I want to do is just give you the measurements of the mounting holes here on the side. Center to center is going to measure right at 7". That should do it for the review on the Reese sidewinder rotating turret premium pin box coupler.

Customer Reviews

Sidewinder Rotating Turret Premium Pin Box Coupler - ST400 - ST400

Average Customer Rating:  4.0 out of 5 stars   (2 Customer Reviews)

This Sidewinder rotating turret premium pin box coupler is designed to work with the Sidewinder standard or super duty arm.

- ST400

Fit as expected.... Very quick delivery.... Although they were no directions how to assemble onto the sidewinder arm or any information on torque specs a simple search took care of that.... I do not believe that was a etrailer issue make it was a manufacturer issue as far as no directions... 791808

- ST400

First one delivered did not fit they shipped another that worked well. 455921


Ask the Experts about this Reese Accessories and Parts

  • Sidewinder Rotating Turret Replacement Pin Box for Leland 7921
    The Sidewinder Rotating Turret Premium Pin Box Coupler - ST400 # ST400 is a fit for the Leland 7921 pin box meaning it will bolt onto your trailer to replace it that pin box. The full rotating pin box to replace your current Leland 7921 is the 5th Airborne Premium 5th Wheel Air Ride King Pin w/ Sidewinder and Turret - 16,000 lbs # ST400-5AS16K.
    view full answer...
  • Recommendation for Applying Grease to Reese Sidewinder Turret
    During initial installation, I recommend applying a good amount white lithium grease like # L11350 to the inner tube of the Sidewinder Turret # ST400 referenced in your question. This will help in fitting the components together for the first time. Along with the turret itself, you will want to apply grease to the surface on both sides of the wedge, the area where the jaw passes under the wedge, and around the king pin and skid plate. Reese also recommends that at least once per season...
    view full answer...
  • Sidewinder Rotating Turret # ST400 Making Popping Sound When Turning
    I contacted our representative at Cequent about the Sidewinder Rotating Turret, part # ST400. He recommended you begin by checking the torque on the top bolts of the turret. You will want to make sure that these bolts are not over torqued, which could be causing the problems you are having. The other thing, since the unit is pointing upward slightly, is to adjust the height of the 5th wheel hitch. But when doing this, you will want to make sure there is at least 6 inches of clearance...
    view full answer...
  • Will Obsolete Sidewinder Turret ST600 Fit the New Sidewinder Arm # SW16K
    None of the available Sidewinder turrets are a confirmed fit for the Leland 7930 pin box. If the ST600 is and you can find one then grab it while you can! There are only models for the 7910, 7920, and 7921 pin boxes. They use the ST400 turret # ST400. You can take some measurements of your pin box, see link to the right, to determine if the measurements are the same as the above mentioned pin boxes and if so then you could use an ST400 set up.
    view full answer...
  • Dimensions of Pin Box Coupler # ST400 and What Pin Boxes it Will Fit
    I certainly can. I went out to the warehouse and pulled the mounting part, # ST400, and did the measurements myself. The Sidewinder Rotating Turret Premium Pin Box Coupler, # ST400, is made to fit pin boxes: Leland 7910, 7920, and 7921; 5AB-E7920; Demco-GR19LND7920; Trail Air-L08; Mor RPB72-7920. If looking at the box from the side, it is 13-1/2 inches long at the base, and 9-3/4 inches long at the shortest point (nearer the top). It is 8-1/8 inches tall at the tallest point. It is...
    view full answer...
  • Replacement Rotating Turret for a 5th Airborne Sidewinder from Lippert Pin Box to Leland Pin Box
    You will need the Sidewinder Rotating Turret Premium Pin Box Coupler, item # ST400, to switch the Lippert rotating turret to a Leland rotating turret on your 5th Airborne Air-Ride Sidewinder. You can review the conversion table (see link) to see the parts for both Leland and Lippert pin boxes.
    view full answer...
  • Tips for Fitting the 5th Airborne Sidewinder Standard Arm Into the Rotating Turret
    I actually had the pleasure of fitting these two components together once and found that the fit is very tight. Most important thing to do is use a liberal amount of white lithium grease like part # L11350. I found that once you start the # 5AS16K into the # ST400 the easiest way to make it slide all the way in is to flip the assembly upside down, put blocks underneath the side that's unsupported so that its sits level, and then use a block and hammer to drive the pieces together.
    view full answer...

Do you have a question about this Accessories and Part?

  • Why etrailer.com?

    At etrailer.com we guarantee:
  • Highest quality accessories and parts for the best price.

    Our Lowest Price Pledge ensures you will never overpay for the parts you need.
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate accessories and part information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Installed by:
Jeff D
Expert Research:
Reno H
Updated by:
Sarah W
Updated by:
Alexander C
Updated by:
Hannah L

At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.