When pulling my trailer my truck drops down and tachs out to 3000 rpm and it really strains when getting to some hills I dont think this was like this the first year of me owning this,How can i tell if something is wrong I did limp the tranny twice and then pulled the tune out and left it stock.The trailer weighs 7500lbs and car 2600 and tools maybe 1000 etc with generator I know its alot of weight.But seems guys are towing the same.I also hit hills and the water temp rises if i keep my foot in it.I just lost a head gasket in it saturday and i think it even bent a rod cause iit makes the noise indicating so I am not happy but i know some of this is self inflicted but these trucks all seem to have head gasket problems.I had the injectors go out at 116,00.any help from you guys that know will be appreciated. I am thinking of fixing and getting rid of this truck but maybe the tranny is bad and working motor to much but it feels ok when not towing thanks Dave