New 2026 Forest River RV Sierra 3990FL Fifth Wheel

3 A/Cs & Tankless/On-Demand Hot Water Heater
Virtual Tour Front Living Fireplace
2026 3990FL Features and Options

Forest River Sierra fifth wheel 3990FL highlights:

  • King Bed
  • Front Living Area
  • Two Tri-Fold Hide-A-Beds
  • Theater Seating

 

The perfect fifth wheel for a larger family! This unit sleeps eight people the loft above the rear master bedroom and bathroom. In the loft area, there are two 44" x 74" bunk mats for comfort as well as wardrobe/storage at the head of each. The master bedroom features a king size bed that slides out to create more space by the bed. A spacious bath features a one-piece fiberglass shower for comfort.  A spacious kitchen features two slides, a free-standing dinette in one, and the 12V refrigerator and stove in the other. There is also a center island with large sink for added food prep space. Head up the steps in front to a dual slide front living area with 50" TV and fireplace beneath the window. There is also theater seating opposite the TV, and a tri-fold hide-a-bed in each slide allowing added sleeping space when needed.

 

Each one of these Forest River Sierra fifth wheels are equipped with everything you need to make the most of each adventure! The underbelly armor will protect your unit's vitals from road debris and the painted two-tone aerodynamic fiberglass front cap has an improved turning radius to make them easier to navigate. With an electric leveling system, you can set your unit up quick and easy then get to having fun faster than ever. The cambered powder coated frame with rust prohibitor construction allows for more duration of the fifth wheel. Each model also comes with a TV antenna with booster, 60,000BTU on demand tankless water heater, Goodyear Radial tires with 7,000 lb. axles, and the list goes on. The interior is just as impressive with Beachside Sundance Congoleum linoleum, recessed residential lighting, a memory foam mattress, and hidden hinged, soft close drawers and cabinets!

Options:
  • 3RD 15K AC W/POWER MANAGEMENT
  • CHEF'S KITCHEN PKG
  • PORTABLE VACUUM
  • RVIA SEAL
  • SUMMIT PKG
  • TWO DINETTE CHAIRS IPO BENCH
What Our Customers Are Saying

Fantastic service and support!

Fantastic service and support. Jim and Mike know RVs and even more important know the industry and all the conditions that are affecting RV sales. In addition, RV Kountry went above any beyond when it comes to the sale of my coach. They coordinated battery replacements and other repairs. I would highly recommend RV Kountry. Thanks for all your help. - Greg
Price: $100,861
You Save: $20,864
Sale Price: $79,997
Ron Hoover RV & Marine Centers
Location: Texarkana
Stock# 87678


2026 3990FL Specifications
Sleeps 8
Slides 5
Length 43 ft 6 in
Ext Width 8 ft
Ext Height 13 ft 4 in
Int Height 7 ft
Interior Color SWITCHBACK
Exterior Color BEIGE
Hitch Weight 2825 lbs
GVWR 15375 lbs
Dry Weight 12439 lbs
Cargo Capacity 2936 lbs
Fresh Water Capacity 50 gals
Grey Water Capacity 80 gals
Black Water Capacity 50 gals
Furnace BTU 40000 btu
Available Beds King
Refrigerator Type 12V
Refrigerator Size 16 cu ft
Cooktop Burners 3
Number of Awnings 1
Axle Weight 7000 lbs
LP Tank Capacity 30 lbs
Water Heater Type On Demand Tankless
AC BTU 30000 btu
TV Info LR 50" Flat Screen Smart TV
Awning Info 21' Electric w/LED Light Strip
Axle Count 2
Washer/Dryer Available Yes
Number of LP Tanks 2
Shower Type Standard
Electrical Service 65 amp
VIN 4X4FSES20TJ055153
For more information Contact Us
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