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Jayco Seismic 403

Fifth wheelbuilt 2023–25Mixed build tierFindable on the used market
WHAT ONE COSTS
$85,700est. used (2025, 1 yr old; from 4 priced floorplans of this line)
WHAT IT WEIGHS BEHIND YOUR TRUCK
~14,944 lbestimated as towed, for 2 people

dry weight 13,260 lb + fresh water (106 gal, full) 884 lb + propane + battery 200 lb + gear for 2 600 lb. Brochure dry weight omits water, propane, batteries and your gear; this estimate doesn't.

You want a tow rating around16,605 lb (10% margin)
GVWR (the sticker maximum)16,500 lb
Tongue weight, loaded~3,370 lb (23%)
Cargo capacity3,240 lb
WHICH TOW VEHICLES IT FITS: 19 OF 95

Judged the way the app judges: estimated loaded weight against each vehicle's rating less a 10% margin, per model year, because the 403's published weights changed mid-run. Fifth wheels also need a pickup bed and are held to the fifth-wheel rating where published.

VEHICLETOW RATINGVERDICT
Chevrolet Silverado / GMC Sierra 2500HD (Duramax, max tow) '24-2622,500 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 2500HD (Duramax) '20-2318,510 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 2500HD (Duramax) '11-1918,100 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 3500HD (Duramax DRW, gooseneck) '20-2636,000 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 3500HD (Duramax DRW, gooseneck) '11-1923,300 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 diesel, gooseneck) '20-2222,800 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 diesel, tow pkg) '17-1918,000 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 diesel) '11-1616,600 lb2023 model years fit
Ford F-250 Super Duty (6.7 HO diesel, gooseneck) '23-2623,000 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 diesel DRW, gooseneck) '17-1932,500 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 diesel DRW, gooseneck) '20-2237,000 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 diesel DRW, gooseneck) '11-1621,600 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 HO diesel DRW, gooseneck) '23-2638,000 lbfits, loaded, with 10% margin
Ford F-450 Super Duty (6.7 HO diesel DRW, gooseneck) '23-2640,000 lbfits, loaded, with 10% margin
Ram 2500 (6.7 Cummins HO) '19-2620,000 lbfits, loaded, with 10% margin
Ram 2500 (6.7 Cummins) '11-1817,980 lbfits, loaded, with 10% margin
Ram 3500 (6.7 Cummins DRW, gooseneck) '13-1831,210 lbfits, loaded, with 10% margin
Ram 3500 (6.7 Cummins HO DRW, gooseneck) '25-2636,610 lbfits, loaded, with 10% margin
Ram 3500 (6.7 Cummins HO DRW, gooseneck) '19-2437,090 lbfits, loaded, with 10% margin
The 76it doesn't fit

These verdicts assume 2 people aboard with typical gear. See the margin for your truck and your crew →

THE SPECS
Length41.5 ft
Height (incl. A/C)13.3 ft
Width8.5 ft
GVWR16,500 lb
Dry weight13,260 lb
Dry tongue weight2,990 lb
Cargo capacity3,240 lb
Sleeps7
Axles2
Fresh water106 gal
Grey water87 gal
Black water87 gal
Awning20 ft

A missing row means the maker never published that figure: unknown, not zero.

WHERE PEOPLE SLEEP
  • 1× Front bedroom queen(Permanent)—
  • 1× HappiJac electric-lift queen in garage(Stow-away)—
  • 1× Garage convertible sofa(Convertible)—
  • 1× Free-standing dinette(Convertible)—
HOW IT'S BUILT: 4/5
WallsLaminated fiberglass
FrameSteel
RoofWalk-on
UnderbellyEnclosed

Jayco (Mixed tier): Jayco

YEAR BY YEAR: WHAT CHANGED
YEARSGVWRDRYMSRP
202316,500 lb13,130 lb—
2024–2516,500 lb13,260 lb—
  • 2023Introduced
  • 2025Dealer stock only
  • 2026Discontinued
FINDING ONE

Findable: a few listed nationwide most weeks. Why: Jayco is a volume manufacturer. Estimated from build volume and production span, not a count of live listings.

OUR TAKE

Lightest of the long Seismics; wound down to dealer-stock-only in 2025.

OTHER SEISMIC FLOORPLANS
359 · 17,500 lb · sleeps 6395 · 21,000 lb · sleeps 7399 · 21,000 lb · sleeps 8405 · 16,955 lb · sleeps 9413 · 20,800 lb · sleeps 6the whole line →
Find one for sale

Live listings for the 403 on the big marketplaces. Each search opens pre-filled with this exact floorplan:

RV Trader ↗Camping World ↗FB Marketplace ↗Google ↗

Inventory varies by site and day. Slim pickings? search the whole Seismic line ↗

Is the 403 your #1, or just a spec sheet?

These are the facts. Whether it beats the other six thousand rigs for you depends on what you care about. Set your priorities as sliders, switch on your hard limits, and watch the whole market re-rank around them. Every exclusion explained, every margin shown.

See where it ranks for you →

Data compiled from manufacturer spec sheets, retrieved 2026-07.