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Demco 5th Wheel Rail Adapter for Chevy/GMC OEM 5th Wheel Towing Prep Package - 21K

Demco 5th Wheel Rail Adapter for Chevy/GMC OEM 5th Wheel Towing Prep Package - 21K

Item # DM6333
Our Price: $649.00
You Save: $104.00
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Use your standard, above-bed fifth-wheel trailer hitch with your Chevy or GMC factory, underbed 5th-wheel towing prep package. Adapter mounts in factory sockets and supplies mounting rails in your truck bed for attaching your hitch. 1-800-940-8924 to order Demco accessories and parts part number DM6333 or order online at Free expert support on all Demco products. Great prices and Fastest Shipping for Demco 5th Wheel Rail Adapter for Chevy/GMC OEM 5th Wheel Towing Prep Package - 21K. Accessories and Parts reviews from real customers.
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2024 Chevrolet Silverado 2500 - Demco 5th Wheel Rail Adapter for Chevy/GMC OEM 5th Wheel Towing Prep Package - 21K

  • Fifth Wheel Installation Kit
  • Adapters
  • Rail Adapter
  • Demco

Use your standard, above-bed fifth-wheel trailer hitch with your Chevy or GMC factory, underbed 5th-wheel towing prep package. Adapter mounts in factory sockets and supplies mounting rails in your truck bed for attaching your hitch.


  • Converts your factory-installed, underbed 5th-wheel mounting kit from Chevy or GMC to standard, above-bed 5th-wheel base rails
    • Lets you use your 5th-wheel trailer hitch that attaches to standard, above-bed rails
  • Mounts to OEM pucks (or sockets) in your truck bed
    • Unit drops into pucks and locks in place
    • No drilling or welding required
  • Rust-resistant black powder coated steel construction
  • Made in the USA


  • Application: Chevy or GMC trucks with OEM, underbed base rails and 6-1/2' or 8' beds
  • Maximum capacity: 21,000 lbs
  • 5-Year warranty

Note: This adapter will not work with a B and W Patriot sliding hitch.

This adapter is perfect if you want to use your standard fifth-wheel trailer hitch with your Chevy or GMC truck's factory-installed, underbed fifth-wheel mounting kit. Just mount the adapter in your underbed rails using the integrated pucks and lock it place. Now you have the standard, above-bed base rails needed to install your fifth-wheel hitch.

6333 Demco Chevy or GMC Truck OEM Adapter for Attaching Standard Fifth-Wheel Trailer Hitches

Installation Details DM6333 Installation instructions

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Demco 5th Wheel Rail Adapter for Chevy/GMC OEM 5th Wheel Towing Prep Package - 21K - DM6333

Average Customer Rating:  4.8 out of 5 stars   (255 Customer Reviews)

Use your standard, above-bed fifth-wheel trailer hitch with your Chevy or GMC factory, underbed 5th-wheel towing prep package. Adapter mounts in factory sockets and supplies mounting rails in your truck bed for attaching your hitch.


To be honest, I wish I had gotten an 8' bed on my new truck so I wouldn't need to get a sliding hitch. It's very heavy! You have to have an engine lift to put it in and that's not very easy to do either. The arm isn't long enough so you will have to move the hitch around by hand after you hoist it up into the bed. Very heavy! But, if you have a short bed truck it's the only hitch to get to protect your cab.

Etrailer Expert

Katrina D.


Oh yeah, sliding hitches are way heavy! I always make sure to use a second person to help carry just half of one. It's definitely worth the weight though, your truck will thank you. We use a forklift sometimes to help us lift one to the bed of a truck.


This adapter allowed me to use the
Curt A16 hitch I already owned. This DEMCO 6333 adapter is an absolute monster. Incredibly well built with precise machining. The hitch fits very well.
Since each truck is built within a certain tolerance and slightly different I had to make a minor adjustment to the lock down positions to get the perfect fit. By loosening all 4 bolts on each of the lock down handles I was able to get the adapter to drop right in place.
Comparing this adapter to others is no comparison.
This DEMCO 6333 is much sturdier.
I added a picture of the Curt A16 mounted on the DEMCO 6333 under the LUND Tri-fold cover. Overall, this is a great combination.
I wanted to be sure to say "THANKS" to Montrell (etrailer Rep) who ensured the DEMCO was a proper fir for my truck as well as processing the order quickly. Job Well Done!!



Its been a year and about 5,000 miles. Overall The Demco works well. I dont like noisy, clunking fifth wheel hitches. With some shim adjustments I am able to keep the Demco plate snug in the built-in GM adapter.

Ram 2500

Amy provided excellent advice in helping determine the best choice for a 5th wheel hitch to use with our 2020 GMC 2500 Crew Cab with the 6-3/4' bed. One important factor was the sliding feature on the Demco Premiere which had 8" of travel, rather than the 12" slide on other models. (In reviewing specs on various hitches, it appeared that the 12" slide versions might interfere with the tailgate on the truck.)
The Demco has worked fine for us. We have not needed to use the slide but it is reassuring to know that it is available if we get in a tight maneuvering situation. (The cab corner on our previous truck took a couple of minor hits using a non-sliding hitch.)
The customer service group was very helpful and I was able to assemble and install the hitch and adapter plate with minimal assistance. Shipping was fast and a minor issue was taken care of immediately.

Dodge Ram Pickup

This is an excellent product to use for the Demco auto slider 5th wheel. Follow the directions and it will drop right into the pucks. It's heavy so it will take another pair of hands unless you're Arnold. I'm alone, so I have a 2 ton engine hoist that works real well. My auto slider drops right into adapter rails. An excellent piece of equipment from etrailer. Best place to buy rv equipment. When needed, they're an excellent choice for advice. I might add that this adapter is only for the 2020 Silverado and GMC Sierra. They have different ones for Ford and Ram. I would definitely buy from etrailer again.


Outstanding product. But even more outstanding was Customer Service and expert technical advice. All questions to the technical experts were processed fast and right on with correct answers. Customer service was unbelievable. I called them with a concern on shipment that was being held up. They got right in it and before the evening was gone my shipment was. Processed and at my house in three days. I was in a bind to move my fifth wheel and without a working hitch in my new truck. They came through with the product and shipment so I could move my camper and not have any issues.
As others have said, etrailer is above others on customer service and reliability of product and great technical help. My choice of business when I need something or have to have the correct technical data.
Thanks for the extra effort.


I got a new 2021 GMC with the puck system and I wanted to be able to use my existing Pullrite Superglide 2700 hitch. I looked at the Pullrite adapter...that's a multi-piece rail system and was thinking more likely to rattle. Found this Demco adapter which is one piece and a better price.

Just put the adapter (and the hitch) in the truck this morning. Following the instructions, loosened the bolts and it dropped right in. The only thing that would've made this better is if the temp was above freezing.

2020 Chevrolet Silverado 3500

I love the adapter. Received it really fast, and it dropped in and fit really well. I have a 2020 Chevrolet Silverado 3500hd, with fifth wheel prep package. I also have a Curt E16, with A16 slider to use on it.


Excellent product, I bought a 2020 GMC diesel the rail adapter fit perfect. As you can see in the picture, a husky fifth wheel hitch fit this adapter. The instructions that come with the adapter made it easy to install.


Excellent service, was able to ship my item to me in 3 days!!! Will always refer friends and family to etrailer! The Demco 6333 fit my 2020 Denali dually perfect so I could keep my 5th wheel hitch...


Just received the adapter and 15 minutes to install. However, you likely will have to loosen the 9/16 bolts on one side to get it to drop into the puck holes then torque back down. Mine was just a 1/32 off and would not drop until I loosened the bolts which allowed the locking tabs to drop into the puck.


It fits the new 2020 Gmc / Chevrolet
has two different sized hitch connections for US standard hitches you got to loosen up where the handles are with a wrench set it down make sure they lineup and then tighten it down and snap it in

2022 Chevrolet Silverado 3500

Product works as advertized. I paired this mounting plate with the Curt A24 hitch and they seem to be a good combo for my towing needs. No complaints


Had purchased a Demco slide hitch for our Nissan TitanXD. Sold that truck and ordered this hitch plate for our 2023 GMC 2500HD. Perfect fit. Great customer service and support.

Chevrolet Silverado

First time using etrailer. The whole process from ordering to delivery was great, placed order on Tuesday and received it on Thursday. I was kept informed through the entire process. I ordered the Demco dm6333 adapter to be used with a Pullrite 2700 SuperGlide that i already owned. Used the dm6333 adapter in a standard bed 2020 Silverado 2500 that had factory pucks. Had to loosen the bolts on the locking handle plates to get the adapter to drop in the pucks but that was expected from posts I saw on line, no problem. Mounted 2700 SuperGlide to adapter just fine. Trailer is 7 inches above bedrails and good clearance when turning. Trailer is about 2 inches from level but I don't think that is a problem. Demco's dm 6333 seems to be what i needed without having to purchase a new hitch.



After a year, still pleased with the Demco dm6333 hitch adapter, works for me.

2020 Chevrolet Silverado 3500

Just had to make a small adjustment to fit the puck system but in the end, fit perfectly and seems fairly tight. My Reese slider hitch fit perfectly.


Thank you and the product is everything I was looking for. All aspects of the service was great . Again Thank you



I installed it and walked away with no issues- highly recommended


Easy installation.


Easiest puck system plate I have used in the last 3 GM trucks I have owned.


Very easy to installed and remove.The only thing I don't like is that it doesn't lock in tight. And when the 5th wheel is hooked up to the camper you can hear and feel the rail adapter moving when you taking off and slowing down.

Etrailer Expert

Brooke M.


Thank you for your review! A few things to keep in mind when using this adaptor. Since it can be used with different manufacturers, there may be little bit of play in how things fit from brand to brand, and in the puck openings, dirt and debris can get caught there, too. If it were a perfect fit, the debris would eventually lock the adaptor in place permanently, the having a little but of room helps prevent this from happening. I hope this helps!

2022 Chevrolet Silverado 2500

I was able to order however I needed help on some technical questions bet could not get anybody on the phone, parts came in however I needed another part to complete my order, I had to call the manufacturer of Demco and they were very helpful, now it’s going to be two more weeks before I get another part so I can haul my RV. The products are Demco 5 th wheel slider, it seems to be made well however I wont know until I receive another part.

Etrailer Expert

Sierra K.


Sorry for the confusion. Yes, item #DM8550034 goes with the installation kit.


Would not buy again!!! The welds that hold the pins in place broke free. Looks like no weld penetration. Each pin has four welds holding in place. One pin came completely loose, all four welds broke loose. Two others pin only held in place by one weld, I could have slid a dollar bill under the other three welds. So three out of the four pins that hold the base plate to the truck had failed. I’m so glad I made it home after my last trip and I’m so glad I caught the issue before this trip. Luckily I have a welder and was able to repair myself or my trip would have been ruined. I don’t recommend this product, major safety hazard!!!!

2020 Chevrolet Silverado 3500

Product is very well built. Installation would have went much quicker had there been directions explaining to loosen the 4 9/16 bolts at each handle to allow play for the adapter to fall into pick system. Then retighten bolts. What should have taken 10 minutes took over an hour and reading others reveiws.


Adapter arrived earlier than promised. Was able to install it with help from my son without any problems and my existing hitch slid right onto it.

Thanks Gwen for the great advice and service!



Still working great!


After having this hitch for one year, I’m pretty disappointed. This hitch has the most play of any hitch I’ve ever had. The curt hitch I have has no play. Also the the handle for the slide is not very user friendly. If you pull it too hard it will simply pull out of one side. It will get the job done if you don’t have any other choice. The only reason I purchased this brand was because it was the only brand I could get during Covid.


Purchased the demo 5th wheel adapter plate for my 2023 gmc 3500 .it was very easy to install with no issues. Would recommend purchasing it from e trailer.the staff was very helpful.

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