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Forest River Sierra 379FLOK

Fifth wheelbuilt 2017–21Mixed build tierFindable on the used market
WHAT ONE COSTS
$45,600est. used (2021, 5 yr old)

Sticker was $74,252 in 2021. Out of production since 2021, so the used market is the only way to buy one. Estimate assumes a 2021 unit.

WHAT IT WEIGHS BEHIND YOUR TRUCK
~14,369 lbestimated as towed, for 2 people

dry weight 13,069 lb + fresh water (60 gal, full) 500 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 around15,970 lb (10% margin)
GVWR (the sticker maximum)16,069 lb
Tongue weight, loaded~2,823 lb (20%)
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 379FLOK'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 lbfits, loaded, with 10% margin
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
Length42.8 ft
Height (incl. A/C)13.4 ft
Interior height7.0 ft
GVWR16,069 lb
Dry weight13,069 lb
Dry tongue weight2,568 lb
Sleeps6
Slide-outs5
Axles2
Fresh water60 gal
Grey water134 gal
Black water52 gal
Air conditioning15,000 BTU

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

WHERE PEOPLE SLEEP
  • 1× Rear private bedroom king(Permanent)72×80
  • 2× Front living room sofas and dinette convert(Convertible)—
HOW IT'S BUILT: 4/5
WallsLaminated fiberglass
FrameAluminum
RoofWalk-on
UnderbellyEnclosed

Forest River (Mixed tier): Sierra is the Sandpiper's badge twin - welded aluminum-framed laminated construction, mid-pack Forest River quality control.

YEAR BY YEAR: WHAT CHANGED
YEARSGVWRDRYMSRP
2017–1915,500 lb13,069 lb$74,252
2020–2116,069 lb13,069 lb$74,252
  • 2017Introduced at 42'9" with a 15,500 lb GVWR and 2,495 lb pin
  • 2018Length listed at 41'9"
  • 2019Length listed at 41'5"
  • 2020GVWR raised 569 lb to 16,069 lb, pin to 2,568 lb; length back to 42'9"
  • 2021Final model year
FINDING ONE

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

OUR TAKE

Six-slide front-living palace that only makes sense behind a dually - grand inside, brutal to park and to tow.

OTHER SIERRA FLOORPLANS
2850RL · 10,000 lb · sleeps 6321RL · 13,669 lb · sleeps 43250IK · 10,000 lb · sleeps 63330BH · 13,769 lb · sleeps 63370RLS · 13,560 lb · sleeps 43440BH · 14,075 lb · sleeps 63550BH · 15,500 lb · sleeps 83660MB · 14,115 lb · sleeps 6368FBDS · 15,500 lb · sleeps 63710HBFB · 15,500 lb · sleeps 8372LOK · 15,500 lb · sleeps 8373BH · 15,500 lb · sleeps 63770FL · 14,175 lb · sleeps 6377FLIK · 15,500 lb · sleeps 8the whole line →
Find one for sale

Live listings for the 379FLOK 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 Sierra line ↗

Is the 379FLOK 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 dealer and aggregator listings, retrieved 2026-07.