New 2024 Grand Design Momentum 399TH

Location Rockwall, TX


Stock # 11471
MSRP $173,152.00
Sale Price $144,999.00






12 Years



Give Me My Best Price

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The 2024 Grand Design Momentum 399TH is an exceptional and spacious fifth-wheel toy hauler designed for adventurers who demand the perfect fusion of luxury and functionality. Measuring approximately 44 feet in length, this model is the epitome of versatility, providing ample space to bring your favorite recreational vehicles along for the journey. The exterior design is both rugged and visually striking, built to withstand the challenges of off-road travel while making a bold statement.

Inside the Momentum 399TH, you'll find a beautifully appointed living area that prioritizes both comfort and style. The main living space includes multiple slide-outs, creating an expansive and inviting environment. The living room features luxurious seating, an electric fireplace, and a large LED TV, creating a cozy and entertainment-centric space. The well-equipped kitchen is a chef's delight, boasting high-end appliances, solid surface countertops, and a residential refrigerator, ensuring you can prepare gourmet meals even in remote locations. The master bedroom offers a serene retreat, complete with a comfortable king-size bed, extensive storage options, and a washer and dryer prep area for added convenience during extended journeys.

The 2024 Grand Design Momentum 399TH offers a superb outdoor experience as well, with an electric awning and LED lighting for outdoor leisure. The spacious garage area features a heavy-duty ramp door and offers ample room for storing and accessing your recreational vehicles or equipment. This model is also equipped with advanced safety features, automatic leveling, a comprehensive climate control system, and state-of-the-art entertainment technology. In summary, the Momentum 399TH is the ultimate choice for those who desire an adventure-packed, luxurious toy hauler that can withstand the rigors of the great outdoors while providing all the comforts of home.



Sleep Capacity:


Water Capacity - Black:

104 gal

Water Capacity - Fresh:

140 gal

Water Capacity - Grey:

104 gal

A/C Spec:

30000, BTU's

# of A/Cs:



20,000 lb

Dry Weight:

15,900 lb

Payload Capacity:

4,100 lb

Hitch Weight:

3,400 lb

# of Slideouts:


# of Axles:


Stock #:





Rockwall, TX


1 miles







Secondary Type:

Fifth Wheel


44' 9"


8' 5"


13' 6"

  • Appliances
  • Microwave
  • Oven
  • Refrigerator
  • Stove Top Burner
  • Water Heater
  • Electrical
  • Air Conditioning
  • Auxiliary Battery
  • Equipment
  • CO Detector
  • LP Detector
  • Smoke Detector
  • TV
  • Exterior
  • Awning
  • Exterior Speakers
  • External Shower
  • Ladder
  • Leveling Jacks
  • Outside Entertainment Center
  • Power Roof Vent
  • Skylight
  • Slideout
  • Spare Tire Kit
  • Horse / Livestock / LQ / Tack
  • Insulated
  • Interior/Furnishings
  • Bunk Beds
  • Central Vacuum
  • Fireplace
  • Free Standing Dinette w/Chairs
  • Medicine Cabinet
  • Queen Bed
  • Rocker Recliner(s)
  • Roof Vents
  • Shower
  • Toilet

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Dealer Information

McClain's RV Rockwall

2505 E. I-30 Rockwall, TX 75087

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2024 Grand Design Momentum 399TH Gallery

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