Does the title need a notary or witnesses?
Neither — unless a lender holds your title
For an ordinary sale, no. Tenn. Code § 55-3-118(a) has the owner endorse an assignment and warranty of title on the certificate, with a statement of all liens, and deliver it to the buyer when the vehicle is handed over — no notary, no witness. But if a lienholder holds your title, you may give the buyer a separate notarized bill of sale. It must show the lienholder's name and address, and you must tell the lienholder about the sale. The state's rule says you still sign the assignment on the title as well. Joint owners: everyone named signs, unless the names are joined by “or”.
Source: Tenn. Code § 55-3-118(a) and (c); Tenn. Comp. R. & Regs. 1320-08-13-.02(1)(c)