Can anyone help me please? I have the following questions:

If I sell a Business Vehicle, that has not fully depreciated, what journal entry/entries do I need to make to get it off my books? For example, if the Vehicle cost me $25,000, A/D was $18,000, and I sold it for $10,000? I'm new at this, but here is what I'm thinking.

Dr. A/D 18,000
Dr. Cash 10,000
Cr. Gain on Sale 3,000 (25000-18000=7000)
Cr. Cost of Vehicle 25,000

Thank you

Correct.

As for the Gain, that is just a plug number. But if you want to calculate it:

Car 25,000 – AD 18,000 = Book Value of 7,000. You sold it for 10,000, therefore you have a 10,000-7,000 = $3,000 Gain