Looking for information on purchasing wrecked trucks.

No insurance company is going to sell direct to a salvor. They all have contracts with the major salvage auction houses like Copart or Insurance Auto Auctions (IAA). You may find a large fleet that would concider a direct sale, but the insurance companies process so much salvage they don't want to deal with indvidual buyers.

Also, given there are large payouts to the towing companies that cleaned up the wreck you would need to front large sums of money on behalf of the insurance company just to get the trucks released from impound. Usually the salvage auction pays the towing and recovery invoice then gets paid 30-45 days later from the insurance company.

Now, you may have some luck with heavy duty towing companies since about 40% of all impounds go unpaid. Usually they are required to hold auctions to dispose of the abandoned vehicles and there are few bidders although some can sell direct to the public without auction. This may give you access to truck salvage at a lower price point, or at least with lower buyer fees and without being a licensed dealer, salvor or dismantler.

You may also want to check out online only auctions like Peak or ACV although I am nit sure how much heavy truck salvage they have.