Looks like your gonna have to look at:
www.trucktraders.com look up ones that compair to yours in age and equipment. While your there take note of how many THOUSANDS of trucks are for sell. Note how many REAL CLEAN trucks are there and in GREAT shape. And then be realistic when judgeing the condition of your rig.You should have already known anyway. Its your largest business asset aint it? If you live near the Mexican border then the parts are worth more than the sum.
With most O/O tradeing in their tractors at two years with 500,000 miles. I think we can expect to pay only 45% of new so figure wholesale is 25 or 30 % of new at two or three years old. Something like that. I have trucks to sell too and I hate to think what I'm gonna get for them. Fixing older trucks used to be a great tax deduction. I dont think that applies now.
Life is what happens to you while your busy makeing other plans.