need advise

looking for some advise from some seasoned veteran drivers. i currently own a 2007 int 9400 with isx. currently have about 3000 miles under 1.2mil. just started experiencing oil leaking from blowby tube while under a load but not while empty. currently i loose about 2 to 3 gallons a week depending on my driving habits while loaded. i am guessing we are getting close to that time to replace or inframe this truck. i check my mpg at every fill and average is 6.5 mpg. my questions are how much longer can i get out of this engine. should i just invest now in fixing it or get the most i can out of it..oil pressure is about 37lbs just after a service and around 32 lbs just before. my second question is inframe or reman..got a quote from dealer for $45000 for reman engine trans and clutch with radiator and air charge cooler. cummins says $38000 for reman engine and clutch..or then i found a shop who will inframe engine with new cams radiator and air charge cooler plus reman trans and clutch for $29000. dealer offers 1yr warranty parts and labor. cummins 2yr parts and labor. shop 1yr 100000 mi warranty parts and labor. i am able to swing either of the three but need to know witch one makes the most sense. thanks for the help

 

i ran into a old timer and he told me it could be the turbo building to much pressure in the crankcase and taking oil with it through the tube. im not sure i have ever heard of a turbo being the blame for something like this.

 

last oil sample in september service came back all numbers within normal range..

 

well i dont mind going through three gallons a week if i can squeeze another year out of her. i would just hate to throw a rod or something and ruin the block.

 

the wife says the same due to the extra year of warranty. also the entire bottom of the engine and undercarriage are soaked with oil. no dripping during idle and very minnimal smoke.