As a mechanic I would never recommend towing any automatic car with the drive wheels on the ground. Reason being is the engine drives the input shaft on the transmission and the input shaft drives the fluid pump. In Neutral/Park the clutch packs are not engaged but the main shaft spins because its fixed to the input shaft, clutch packs attach to the output shaft and those make connection of main and output shaft. Fluid is supplied for lubrication and cooling of moving parts. So when the engine is not running and you tow with the drive wheels on the ground the transmission output shaft is spinning because its driven by the drive wheels moving while towing. Lots move moving parts are running dry and heating up shortening the life of internal components. A manual however doesn't have a pump but oil is slung from the gears on the counter shaft, that is usually attached to the output shaft by the output gears, to cool and lubricate parts and usually doesn't matter if the drive wheels are on the ground. I haven't had any experience with the Manual transmission in these so don't take my word on it. I will say if the owners manual says tow with drive wheels off the ground for both automatic and manual transmissions I would follow it, better safe than sorry.
