Yes you can...unloaded and in a case..doesn't have to be locked.
Transporting Firearms
750.227d Transporting or possessing firearm in or upon motor vehicle or self-propelled vehicle designed
for land travel; conditions; violation as misdemeanor; penalty.
Sec. 227d.
(1) Except as otherwise permitted by law, a person shall not transport or possess in or upon a motor vehicle or any
self-propelled vehicle designed for land travel a firearm, other than a pistol, unless the firearm is unloaded and is 1 or more of the following:
(a) Taken down.
(b) Enclosed in a case.
(c) Carried in the trunk of the vehicle.
(d) Inaccessible from the interior of the vehicle.
(2) A person who violates this section is guilty of a misdemeanor, punishable by imprisonment for not more than 90 days, or a fine of not more than $100.00, or both.
History: Add. 1981, Act 103, Eff. Mar. 31, 1982.
750.231a A person is now permitted to transport a pistol for a lawful purpose if the owner or occupant of the vehicle is the registered owner of the firearm and the pistol is unloaded and in a closed case in the trunk of the vehicle. If the vehicle does not have a trunk, the pistol may be in the passenger compartment of the vehicle unloaded and inaccessible to the occupants of the vehicle.
A 'lawful purpose' includes: But not “limited to”;
• While en route to or from a hunting or target shooting area.
• While transporting a pistol to or from home or place of business and a place of repair.
• While moving goods from one place of residence or business to another place of residence or business.
• While transporting a licensed pistol to or from a law enforcement agency for the purpose of having a safety inspection performed (registering the pistol) or to have a law enforcement official take possession of the pistol.
• While en route to or from home or place of business to a gun show or place of purchase or sale.
• While en route to or from home to a public shooting facility or land where the discharge of firearms is permitted.
• While en route to or from home to private property where the pistol is to be used as permitted by law, rule, regulation, or local ordinance.