I'm guessing you have more 1000 lbs of tongue weight. Do you have a local weigh station where you can go and get scale weights of your axles with and without the toy hauler hitched up?
I use to load my Weekend Warrior tail heavy to keep withing my WDH receiver ratings of 1250 lbs tongue and 12.5K lbs trailer. My F250 truck handled the weight without a problem because it had the heavier spring pack with the camper package - You may end up having to upgrade to a higher capacity receiver and rear springs once you get actual weights and know what you're dealing with.