Demco | 21K 5th Wheel Hitch with Rails | Above Bed Mount | 8550036

Get a complete short-bed fifth wheel towing solution for heavy rigs with the Demco Hijacker 21K Autoslide Above-Bed Fifth Wheel Hitch with Industry Standard Rails (Part #8550036). With 21,000 lbs of capacity, an automatic 14" rack-and-pinion slider, and industry-standard above-bed bed rails included, this is the complete-package option — everything you need to mount and tow without sourcing rails separately.

Complete Kit — Industry Standard Bed Rails Included

What sets the 8550036 apart from the otherwise-identical 8550035 above-bed hitch: the industry-standard bed rails are included in the kit. If your truck doesn't already have rails installed, this is the one-stop option that gets you up and towing without a separate rail purchase. The hitch is also compatible with Premier/Ultra-Series above-bed install kits.

21,000 lb Capacity Built for Heavy Rigs

The 8550036 is rated for serious work with 21,000 lbs of gross towing weight capacity — putting it in the right range for big fifth wheels, toy haulers, and heavy RV setups. Made in the USA with American steel and backed by a 5-year warranty.

Automatic Sliding for Tight Turns

The built-in rack-and-pinion automatic slider provides up to 14" of fore/aft travel at slow speeds — as you turn, the hitch head glides smoothly toward the tailgate to keep your trailer clear of the cab. No need to get out of the truck to pull a pin or manually slide the hitch.

Wraparound Jaw with Locking Bar

The wraparound jaw with locking bar delivers a smoother, safer, and more secure connection to your king pin — cutting down on the rattle and trailer movement that wear on you over a long travel day.

Adjustable Hitch Height for Level Towing

Three height settings let you fine-tune trailer height for level towing and proper bed rail clearance:

• Low: 15-1/4"
• Middle: 16-1/2"
• High: 18"

Lower Profile, Lighter Weight

The 8550036 features a lower profile design and lighter weight than many comparable hitches, making installation and removal easier. Easy access for routine maintenance is built in.

Standard Pin Boxes Activate the Slide Automatically

For most setups, no locking plate is required to activate the slide mechanism — standard pin boxes do the job out of the box.

⚠️ Cushioned Pin Box Requirement

A locking (capture) plate is required for the slide mechanism to activate with the following cushioned suspension pin boxes:

• Demco Glide Ride
• MorRyde
• RotoFlex
• TrailAir Tri Glide
• TrailAir Flexair
• 5th Airborne

⚠️ Note About 90-Degree Turns

This hitch may allow 90-degree turns, but not in every case. The actual maximum turn angle depends on your specific truck and trailer combination, so always check clearance on your setup before assuming full-range articulation.

Considering Other Demco Hitches?

We carry related Demco fifth wheel hitches for different truck setups and capacity needs:

• Demco Hijacker 21K Autoslide WITHOUT rails (8550035) — same hitch, for customers who already have above-bed rails
• Demco Autoslide 18K above-bed (8550034) — same Autoslide platform with 18K capacity
• Demco UMS Under-Bed 18K Autoslide (8550022) — Autoslide with under-bed mounting (18K)
• Demco UMS Under-Bed 21K Autoslide (8550037) — same 21K Autoslide with under-bed mounting
• Demco 21K Ford Prep Package Autoslide (8550038) — same 21K Autoslide, drops directly into factory Ford pucks
• Demco Hijacker SL 21K Underbox (8550033) — same 21K capacity, fixed mount (no slider), for long-box trucks

What's Included (and What's Not)

Included:

• Hitch
• Industry-standard bed rails

Sold separately:

• Vehicle-specific frame brackets — required for installation
• Capture plate — required only if you have one of the cushioned pin boxes listed above

Key Features

• Complete kit — industry-standard bed rails included
• 21,000 lb capacity
• 14" automatic slider using rack-and-pinion gear technology
• Wraparound jaw with locking bar
• 3 vertical height adjustments (15-1/4", 16-1/2", 18")
• Lower profile, lighter weight for easier install and removal
• Easy access for routine maintenance
• No locking plate required for standard pin boxes
• Compatible with Premier/Ultra-Series above-bed install kits or industry-standard rails
• Made in USA with American steel
• FREE freight shipping to the 48 states (freight items are not returnable)
• Backed by a 5-year warranty

Specifications

• Brand: Demco
• Model: 21K 5th Wheel Hitch with Rails (Hijacker Autoslide Ultra Series Above-Bed Mount)
• Part Number: 8550036
• Type: Slider Fifth Wheel Hitch (for short truck beds)
• Capacity: 21,000 lb
• Slider Travel: Up to 14" (automatic, rack-and-pinion)
• Rail Type: Industry standard (included)
• Compatibility: Premier/Ultra-Series Above-Bed Install Kits or Industry Standard rails
• Hitch Heights: 15-1/4" / 16-1/2" / 18"
• Material: American steel
• Includes: Hitch, industry-standard bed rails
• Sold Separately: Vehicle-specific frame brackets; capture plate (only if needed for cushioned pin boxes)
• Cushioned Pin Box Requirement: Capture plate required for Demco Glide Ride, MorRyde, RotoFlex, TrailAir Tri Glide, TrailAir Flexair, 5th Airborne
• Country of Origin: USA
• Warranty: 5-year