Towing Your Subaru Behind A Motorhome
Only manual transmission Subaru's may be towed behind Motorhomes. It is NOT possible to tow an automatic transmission Subaru behind a motorhome, doing so will result in the very quick death of the All Wheel Drive (AWD) systems multi-plate transfer clutch. Even with an automatic transmission cooler with electric fluid pump is installed for towing, the transmission will still fail. The only way to tow an automatic transmission equipped Subaru is on a trailer with all four wheels off the ground
There are no speed or distance restrictions for towing your manual transmission Subaru. Many other manufacturers have a 90kph towing speed limit and a 200km limit between cooling off breaks.
Older Subaru's prior to the 1995 model year with automatic transmissions and All Wheel Drive (AWD) contained a fuse holder under the hood which when a fuse was inserted, the vehicle would switch to front wheel drive mode disconnecting the rear wheels from the drivetrain. This was designed to allow the vehicle to be towed with all four wheels or the two rear wheels on the ground. However there is a speed limit of 50kph and a distance limit of 30km, exceed either of these and the All Wheel Drive (AWD) system is usually damaged. This capability can not be used for towing behind a motorhome.
Some owners complain that their Subaru tends to wander a bit behind the motorhome. A little bit of wandering is to be expected as the suspension system is designed to have the wheels pull the body of the car, and not the body pulling the wheels along such as when be towed. Properly aligned cars will wander less, and apparently reducing the camber will help as well. RV and alignment shops may have more information regarding this, as it is not a Subaru only issue.
Several towbars are available for virtually all Subaru models 1985 and newer. Two types of two bar designs exist, one is attached to the vehicle and folds against the front bumper, the other style is attached to the motorhome and folds against the motorhome. Although I do not own a motorhome and have no direct experience with these systems, the second of the two systems would seem to be better since having a tow bar stored in front of the bumper would defeat some of the safety and damage mitigating abilities of the bumper.
Laws in both Canada and the US require that all towed vehicles be equipped with a braking system that will activate the vehicles brakes in the event that the vehicle becomes detached from the motorhome. These systems are generally referred to as breakaway brakes.
To improve safety and reduce wear on the motorhome's brakes, most owners now install an active braking system. This systems typically sit on the floor between the front seat and a brake pedal. They detect when the towed vehicle is pushing forward on the motorhome and use an pneumatic or hydraulic piston to activate the vehicles brakes to reduce this "pushing" force. These systems also have a connection to the tow electrical harness, during breakaway the harness disconnects and the system activates the vehicles brakes. One of the requirements of this system is an in-motorhome warning light which indicates when the towed vehicles brakes are activated. This warning light is usually connected to the towed vehicles brake lights. This provides a warning to the motorhome driver if the towed vehicles brake system is inadvertently engaged. If the vehicle brakes are dragging without being noticed, they tend to catch fire.
Blue Ox seems to be the most recommended system out there for towing a Subaru. Its tow bar base plates require minor cutting of the plastic bumper cover, but are relatively hidden from view. Blue Ox also produces several braking systems.
Subaru's digital odometers only operate when the key is in the run position, so it will not count the mileage while the vehicle is being towed (with the key in Accessory position). You do however have to keep track of the mileage to determine when the wheels need to be rotated, and the wheel bearings repacked.
Subaru's mechanical odometers require a disconnect accessory, these are available but they are illegal in most jurisdictions. Odometer disconnects, where permissible, immediately void any car manufacturers warranty and any vehicle repair warranty based on mileage. This is because the odometer disconnect can be used to drive "free" miles. Most of these systems are activated by the electrical power from the RV's wiring harness, but it does not take a genius to power it using the vehicle battery.
Since the key must be left in the towed vehicles ignition to unlock the steering system, towed cars can become an easy target for car thieves. There are three solutions: