LC250 rear hatch shudder

anyone else's do this? i'll admit, my cities roads are some of the worst i've ever driven. it's almost like i off-road this thing on my daily commute... that being said, when i hit a bump, it's like the rear hatch is loose and it shakes within the body of the truck. i've looked to see if there are adjustable rubber stops like hoods have that i could adjust out to tighten it, but the stops are not adjustable. so it just kind of closes, but seems loose and prone to shuddering anytime i hit a bump in the road.