Demco | 21K 5th Wheel Hitch without Rails | Above Bed Mount | 8550035

Tow heavy fifth wheels from a short-bed truck with confidence using the Demco Hijacker 21K Autoslide Fifth Wheel Hitch (Part #8550035). With 21,000 lbs of capacity, an automatic 14" rack-and-pinion slider for tight-turn clearance, and a single-piece wraparound jaw for a rattle-free connection, this above-bed hitch is the higher-capacity sibling to Demco's 18K Autoslide — built for big fifth wheels, toy haulers, and serious RV setups.

Built to Tow Heavy Rigs with Confidence

The 8550035 handles big rigs without breaking a sweat:

• 21,000 lb gross towing weight
• 5,250 lb vertical load limit

Heavy-duty steel construction and a black powder coat finish resist rust and road wear, keeping the hitch's solid feel mile after mile. Made in the USA with American steel.

Automatic Sliding for Tight Turns

Short-bed trucks can make tight turns nerve-wracking, but the Autoslide handles it for you. The rack-and-pinion gear system automatically provides 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 pulling levers, no climbing in and out of the truck. When you straighten back out, it slides right back into position automatically.

Quiet, Locked Connection — Wraparound Jaw + 3/4" Steel Locking Bar

The single-piece wraparound jaw fully surrounds the king pin for true 360-degree contact, dramatically cutting down on rattle and chucking compared to slide-bar jaws. A 3/4" thick steel locking bar automatically engages when the jaw closes, reinforcing the connection and giving you peace of mind on rough highways.

Smoother, Quieter Ride

The double-pivot head moves front-to-back and side-to-side to match the angle of your trailer's pin box. Three polyurethane dampeners take the edge off every bump — two cushioning side-to-side movement and one underneath for fore-and-aft — making long drives feel smoother and less jarring.

Adjustable Hitch Height

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

• 15-1/4"
• 16-1/2"
• 18"

The hitch comes pre-assembled — just bolt on the side plates, set your preferred height, and pin into industry-standard above-bed rails (sold separately).

⚠️ Important Compatibility Requirements

This hitch is NOT compatible with Sidewinder or Revolution king pins. Do not use any device that changes the pivot point of your trailer's king pin with this hitch.

If you have a cushioned pin box, locking plates (sold separately) are required for use with the following:

• Glide Ride
• Mor Ryde
• Trailair Tri Glide
• Trailair Flexair
• Rota Flex
• Lippert Road Armor
• 5th Airborne

Fitment

• Designed for 6-1/2' truck beds
• Fits standard pin boxes 12"–14" wide

Considering Other Demco Hitches?

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

• Demco 21K Autoslide above-bed WITH rails (8550036) — same hitch as this one, but includes industry-standard bed rails
• Demco Autoslide 18K above-bed (8550034) — same Autoslide platform, 18K capacity for lighter rigs
• Demco UMS Under-Bed 18K Autoslide (8550022) — Autoslide with under-bed mounting for cleaner truck bed (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

Key Features

• 21,000 lb GTW / 5,250 lb vertical load capacity
• Automatic rack-and-pinion slider — 14" of fore/aft travel
• Single-piece wraparound jaw with 3/4" steel locking bar
• Double-pivot head with 3 polyurethane dampeners
• Adjustable hitch height — 15-1/4", 16-1/2", 18"
• Designed for 6-1/2' truck beds
• Fits 12"–14" pin boxes
• Above-bed rail mounting (rails sold separately)
• Black powder coat finish
• Made in USA with American steel
• FREE freight shipping to the 48 states (freight items cannot be returned)
• Backed by a 5-year limited warranty

Specifications

• Brand: Demco
• Model: Hijacker 21K Autoslide
• Part Number: 8550035
• Type: Autoslide Fifth Wheel Trailer Hitch (single jaw, above bed, without rails)
• Capacity: 21,000 lb GTW / 5,250 lb vertical load
• Slider Travel: 14" front to back (automatic rack-and-pinion)
• Hitch Height Settings: 15-1/4" / 16-1/2" / 18"
• Jaw: Single-piece wraparound with 3/4" steel locking bar
• Pivot Head: Double pivot with 3 polyurethane dampeners
• Truck Bed: Designed for 6-1/2' beds
• Pin Box Compatibility: 12"–14" standard pin boxes
• Rails: Industry-standard above-bed rails (sold separately)
• NOT Compatible With: Sidewinder or Revolution king pins; any pivot-changing devices
• Cushioned Pin Box Requirement: Locking plates (sold separately) for Glide Ride, Mor Ryde, Trailair Tri Glide, Trailair Flexair, Rota Flex, Lippert Road Armor, 5th Airborne
• Material: Heavy-duty American steel
• Finish: Black powder coat
• Country of Origin: USA
• Warranty: 5-year limited