Without a CPL it just needs to be unloaded and in a case. Or just take the slide off and put the frame (unloaded) and slide on your passenger seat (aka taken down).
It's not a felony it's a misdemeanor if you have a loaded gun on you in a vehicle without a CPL
https://www.legislature.mi.gov/THE MICHIGAN PENAL CODE (EXCERPT)Act 328 of 1931
750.227d Transporting or possessing firearm in or upon motor vehicle or self-propelled vehicle designed for land travel; 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 either of the following:
(a) A firearm, other than a pistol, unless the firearm is unloaded and is 1 or more of the following:
(i) Taken down.
(ii) Enclosed in a case.
(iii) Carried in the trunk of the vehicle.
(iv) Inaccessible from the interior of the vehicle.
(b) A pneumatic gun that expels a metallic BB or metallic pellet greater than .177 caliber unless the pneumatic gun is unloaded and is 1 or more of the following:
(i) Taken down.
(ii) Enclosed in a case.
(iii) Carried in the trunk of the vehicle.
(iv) 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.