Here's why:
* Drivetrain: A 4WD system requires a transfer case, front differential, driveshafts, axles, and all the associated components. These parts aren't just bolted on; they require extensive integration with the existing chassis, suspension, and engine. The vehicle's frame may not even be structurally sound enough to handle the added stress of a 4WD system.
* Computer Systems: Modern vehicles have sophisticated computer systems controlling various aspects of the drivetrain. Adding 4WD would require significant changes to this system, potentially involving custom programming or replacement of the entire ECU (Engine Control Unit).
* Brakes and Suspension: A 4WD system puts more stress on the brakes and suspension. Upgrading these components might be necessary to handle the increased load, adding further to the cost and complexity.
* Cost: The cost of parts alone would likely exceed the value of the vehicle. Then you have to factor in the labor costs of a highly skilled mechanic or shop capable of performing such a complex modification.
In short, it's not practical or economical to retrofit 4WD onto a vehicle that wasn't built with it. If you need 4WD, it's far more sensible and cost-effective to purchase a used SUV that already has it.
