b17nka

Hello all
I own a 2001 f150 harley supercrew non super charged,i tow a twin axle caravan here in the uk which is 1800 kg in weight,the other day i got flagged down,i pulled over and under the gearbox it was pouring with gear oil,i checked the oil level and it was still well over half full ,can anyone tell me if it will have damaged the insides of the box or just the pump front oil seal,the gearbox is now out and looks fine but i have been told that the oil seal will have gone is this correct,can anyone tell me why a f150 harley can only tow 1800 kg and a normal f150 can tow 4000 kg according to fords website
thanks for any advice
cheers andy