2021 Grand Design Momentum Interior & seats Problems

I am reporting a serious, progressive structural defect involving excessive frame flex and structural failure on a 2021 Grand Design Momentum 395MS fifth-wheel RV. This complaint directly aligns with the ongoing NHTSA investigation PE24-0209. The unit exhibits clear and worsening structural integrity failure, including: Slideouts and doors open during transport. Upper deck walls moving under load Lag bolts missing or backing out and pushing through flooring At least one critical structural bolt missing from factory installation Floor deformation and slope changes in the upper deck Slide-out malfunction due to frame distortion Loud popping and snapping noises while towing consistent with frame flex or structural separation These conditions reflect loss of structural integrity under normal use and represent a serious safety hazard, including risk of catastrophic failure while towing. On June 24, 2026, Lippert (frame/component supplier) assigned Case #6876203 and scheduled a mobile service inspection. This Grand Design Momentum 395ms is not safe to tow. It is a danger on the roads and they need to be recalled at the least for inspections of the frame for damage.

NHTSA ID

11749089

Incident

Jun 17, 2026

The contact owns a 2021 Grand Design Recreational Momentum. The contact stated that while hauling the RV and driving at undisclosed speeds, the rear side door unexpectedly opened and the slide-out extended outward. No warning light was illuminated. The trailer was taken to a local dealer and remained with the dealer for additional inspections. The RV was not repaired. The manufacturer was made aware of the failure. The failure mileage was unavailable.

NHTSA ID

11727885

Incident

Apr 15, 2022

The contact owns a 2021 Grand Design Recreational Momentum RV. The contact stated while driving 55 MPH, the RV frame flexed. The contact stated that when the RV was loaded, the failure persisted. The contact stated that the screws to the bedroom slide out were detaching. Neither an RV dealer nor an independent mechanic was contacted. The vehicle was not taken to a dealer or an independent mechanic to be diagnosed. The vehicle was not repaired. The manufacturer was notified of the failure and informed the contact to bring the RV to a technician to be inspected. The failure mileage was 15,000.

NHTSA ID

11696350

Incident

Mar 15, 2023

Mileage

15,000 mi

excessive frame flex/failure, Interior cabinetry coming cracked and apart. Floor separating from side walls. Main door coming open during transit.

NHTSA ID

11695772

Incident

Aug 1, 2024

The contact owns a 2021 Grand Design Momentum RV. The contact stated while the RV was parked and occupied, or while driving the RV, there was an abnormal popping and creaking sound coming from the frame of the RV while depressing accelerator pedal or depressing the brake pedal. Neither a dealer nor an independent mechanic was contacted. The contact stated that while driving the RV at an undisclosed speed, the doors opened independently. Additionally, while walking inside the RV, there was an abnormal sound coming from the floorboards. The contact also stated that the frame of the RV was full of rust. The vehicle was not taken to a dealer or independent mechanic to be diagnosed or repaired. The manufacturer was not notified of the failures. The failure mileage was 6,000.

NHTSA ID

11684821

Incident

Aug 15, 2025

Mileage

6,000 mi

Frame failure 2 inches of deflection Doors popped open on hwy walls cracked lag bolts falling out water leaks and floor rotting out from flex

NHTSA ID

11671713

Incident

Jul 7, 2024

FRAME FAILURE AND STRUCTURE. CARGO DOOR OPENED WHILE TRAVELING. (SAFETY ISSUE) FURNITURE SEPARATING FROM STRUCTURE. BROKEN OVERHEAD CABINETS OVER BED (SAFETY ISSUE) WALL SEPARATING FROM FLOOR IN CARGO AREA WOOD DUSTING FROM CEILING IN BEDROOM AND GARAGE AREA.

NHTSA ID

11664700

Incident

May 9, 2025

Excessive frame flex in pin box area of fifth wheel. Forward left cargo door unlatching while towing. Vehicle is currently at Lazydays dealer in TN for inspection and TSB for excessive frame flex. Inspection has revealed major structural cracks and structural failure in upper deck steel frame structure. Vehicle has been deemed unsafe to transport and must be repaired in place or partially repaired for transport to factory. We noticed excessive deformation of the pin box and substantial rubbing of internal cabinets, etc upon return from a recent trip. Based of the damage, it would have been possible for the RV structure to separate from our tow vehicle putting us and others on the road at significant risk of injury or death. We saw indications of interior movement of cabinets and rubbing on walls for several thousand miles, but no indication of significant pinbox deflection until recently. Manufacturer has provided no guidelines or communication to owners to be aware of potential problems or to indicate things to look for that may indicate the vehicle poses a serious risk/hazard. Initial signs of rubbing inside the vehicle, and a loose latch and flapping of cargo door were observed in January 2024. We have video of substantial gap opening and movement of interior cabinets when taking vehicle off of stabilizer jacks and loading onto fifth wheel hitch of truck. Unable to get additional pictures currently as the RV is at the dealer for repairs. Will attempt to get photos of internal frame damage early next week if possible.

NHTSA ID

11636284

Incident

Nov 24, 2024

Side compartments opening while towing unit on highway…items in compartment flying out …hatches won’t closed properly to much gap…big gap also on top cap where it connects to wall in front..unit taken to lazdays Tampa for frame flex recall…inspection revealed major cracks in frame everywhere as a result causing major frame flex…lots of welding is being done…by grand design mechanic ..slide system also damaged as a result of frame flex …unit is currently still at lazdays Tampa being welded together…they keep finding more and more damage …. You guys should send an inspector to inspect it to see major frame damage from poor frame build I believe unit is unsafe to be roadworthy with the amount of welding and repairs to frame the keep doing

NHTSA ID

11636185

Incident

Dec 14, 2024