I have a 2012 Prado Altitude Diesel Auto and do tow a 19 Ft Jayco Caravan with it from time to time. I do not generally use 5th gear, but on occasions when going down hill and if I have a strong tail wind have used it. 5th gear has no noise, but 4th gear does have a whine when towing the van and my assumption is that because it is in 4th gear 90 percent of the time when towing, it may have got some wear. I can't remember if it had the wine from new or if it is normal, but my suspicion is that there is probably some wear because of the van towing in 4th. Any comments from others who use their Prado for towing would be appreciated. I am due for a transmission oil change, so will discuss it with the mechanic then. At the last transmission oil change the mechanic did mention that there was a very small amount of metalic dust on the magnet from memory, but he said that was not abnormal and it was minimal. There is no whine when not towing. Brian DJ