My client has an existing truck loan, and he placed it in the credit card account, when it should be in the long term liability account. What do I need to do?

Create the liability account then do a journal entry, debit the CC, and credit the liability account
There should be a fixed asset account for the truck, and a sub fixed asset account for accumulated depreciation-truck.

the down payment should post to the truck fixed asset account
the loan value should post to the truck fixed asset account
See IRS pub 946 for depreciation

Loan payments are composed of principal and interest, you have to split them out when known each month