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Everything. Look at everything!
Axles were a problem on our non- toy hauler 5er, a brand new unit. Check tires for abnormal wear indicating axle out of alignment. Check springs, mounts, frame welds for bent / cracking. Check roof for damage, seams sealed, no sealant cracking. If equipped, check slide systems for proper operation. Our slim rack kitchen sliedout had nearly every exterior mounting screw head broken off, yet the sealant held them in place. Only way to know was to try to turn them with a screwdriver. Look over leveling system if it's hydraulic, pump area should be dry.
2020 Pinnacle 32rlts
640 watts solar, 300AH lithium
2020 High Country Duramax 3500
Ms says I'm full of useless knowledge and other stuff...