Re: '08 Ford F-250 Towing Compacity
I see this thread is a few months old but needs some in depth review because the answer was a guess and missleading.
As I read the post, the trailer load is specified at 6 to 7000 lbs load 'aside' from the trailer weight.
Without more info on all the weights involved and the truck specs, your 'very' likely way over loaded.
Here is an example guide to this issue.
According to Ford specs the max Gross Combined Wight of both truck and loaded trailer is about 14,000 lbs.
If the truck's weight is 6500 lbs loaded, the trailer load is 6500 lbs and the trailer is a guess at 4000 lbs, the total is
6500+6500+4000= 17,000 lbs.
Without knowing all the data this indicates you may be way over loaded.
Bottom line is never accept a flash answer to this question without checking all the weights involved in the calculation for Gross Combined Weight rateing to be safe and legal.