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We just recently got a Subaru Outback. It is a manual and has AWD. The dealer told us if we need it towed, it has to go on a trailer, and can't be towed with wheels down. I understand that this can cause transmission damage.
My question is, why would this cause transmission damage, when I can pop it into neutral and coast? What is the difference between coasting and being towed?
All wheel drive vehicles connect the front and rear axles via a transfer case or differential. While on a wheel lift tow one set is lifted off the ground and not spinning and the trailing wheels are spinning at road speed. This places a big load and resulting wear on the power transfer unit. Coasting allows all four wheel to spin at road speed but with no engine power applied. I guess you could tow it with an older type of tow rig that used a frame sling lift. The raised wheels could spin freely. Modern vehicles with plastic bumpers wouldn't fair well with this older hoist technology, Which is why wheel lift has become the new standard. It is being replaced by flat/tilt bed rigs due to the increased number of all wheel drive vehicles available.
You can dinghy tow an Outback or Forester behind a motorhome if these conditions are satisfied:
The Subaru is a Manual Transmission model; No automatic transmission subaru should ever be dinghy towed with wheels down!
Use the gray "Valet" key to unlock the steering wheel. This is the first click past the "OFF" position. In this position, the steering wheel lock is disengaged, but the radio, power sockets, and dashboard clock will still be "off". The second click of the key turns on the Accessories (radio, clock, etc). You don't want to use this key position because it will drain the battery.
Keep your primary key, the black one with the push buttons, with you and use it to lock the vehicle's doors and rear hatch. If you don't have a grey "Valet" key, you can get one from a Subie dealer.
Make sure that the Subaru's electronic parking brake is fully disengaged before you take off!
I also own an outback (04) and I have the option to place any amp fuse in the AWD slot located in the fuse box in the engine compartment. This fuse will disengage the rear differential allowing my car to be a front wheel drive only car. This is typically used when there's a flat tire and the spare tire is used. I recommend this for towing as well. Your owners Manuel has this info available.
As I stated in my comment, if you are able to safely let the car idle i.e. the problem isn't your headgasket, ringlands or a burst radiator, you can tow the car with the engine running and someone behind the wheel. From a mechanical perspective this is no different than coasting. I believe the danger with towing the car with the wheels down is that you don't have adequate circulation of your oil to keep the transmission cool. Having the car running will make it safe(r) to tow. A nice bonus is that if you're using a rope to tow the car, the guy steering will have the powersteering active and make his life much easier.
Just don't go fast and try and keep it as short as possible. I would say go 5 miles, then stop and wait 10 minutes. Repeat until you reach where you're going.
