2021 Grand Design Momentum problems & reliability
56 owner complaints filed with NHTSA for the 2021 Grand Design Momentum, alongside 4 safety recall campaigns. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Structure → | 42 | 75% |
| Unknown OR Other | 27 | 48% |
| Suspension → | 17 | 30% |
| Latches/locks/linkages | 9 | 16% |
| Equipment | 3 | 5% |
| Service Brakes | 2 | 4% |
| Electrical System | 1 | 2% |
| Exterior Lighting | 1 | 2% |
| Power Train | 1 | 2% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
Common symptoms owners describe
Keyword analysis of complaint narratives; one complaint can describe several symptoms.
Complaints by incident year
What owners report
“We own a 2021 Grand Design Momentum 393g toy hauler that has severe frame flex and bolts in slide have started backing out. We noticed this when driving and the extreme pushing/chucking when accelerating or braking and also the visible failure on the unit. We have contacted Gran Design, the manufacturer, for warranty…”
Structure · filed Jul 14, 2026
“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…”
Equipment · filed Jul 8, 2026
“Regarding 2021 Grand Design Momentum 376THS: Compartment doors popping open during transport; Grand Design Customer Satisfaction Campaign TSB-24-001 dated 11/1/2025 regarding frame flex and wall securement. Returned to dealer on 12/1/2025 for inspection. Dealer found the following: All doors except p/s compartment…”
Structure · filed May 24, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Federal defect investigations
- Frame Flex on Grand Design Fifth Wheel Recreational Trailers
Preliminary Evaluation PE24029 · opened Oct 9, 2024 · open
Technical service bulletins
2 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2021 Grand Design Momentum.
Grand Design is addressing concerns of excessive frame flex or wall securement in the front upper deck area of a limited number of fifth-wheel units. This condition could potentially occur over time due to a combination…
920017 · Service Campaign · issued Nov 22, 2025
TSB 24-001 Issued in March on March 7th. Concern: Complaint of upper deck flex which results in cosmetic damages to the interior and excessive flex at the pin box. Remedy : The procedure outlined in attached summary to…
TSB 24-001 · Service Bulletin/Repair Instructions · issued Apr 10, 2024
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 2021 Grand Design Momentum has 4 NHTSA recall campaigns — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 2021 Grand Design Momentum?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.