Not even close cummins handsdown.Nothing nowadays will outpull it especially a paccar as far as being reliable i only had 1 egr valve and one egr cooler replaced and had to do one regen.Its a 2010 isx 550 in a 389 pete and never left me stranded only downside is fuel mileage isnt the best.
I have heard a lot about poor pulling in the hills with an MX,,it has been produced and used in Europe for years,,an cummins can be fixed anywhere in the US an MX you might be stuck going to dealers,,with all the EPA required crap it's a toss up, My 08 Peter with ISX I replace 3 turbos, 2 egr valves and one egr cooler in 400,000 miles,,I have a friend with 5 2012 trucks,,3 ISX, 2 Detroit,,tell me he is having better luck with the Detroit diesels ,,If I had a choice ISX or MX I would go with the ISX Cummins,, If you are buying used there are a few places where you can get the EGR,DPF and other EPA stuff removed for between $5k and $10K,,mileage goes up a couple miles per gallon .New turbos like the one on cummins cost about $4K and it makes it worth doing the conversion when your turbo fails,,
Mx uses the same after treatment as cummins because they supply it also same make of Vgt turbo the up charge on a isx is pretty big.. I don't have enough miles on my 2015 mx 485 it pulls decent from 1050 to 1450 rpm any higher and the boost drops ECM keeps a pretty tight rein on power band.. It only has 40000 miles lifetime us mpg is 7.65 on paper running 60 ish pulling 77000 lbs to 100000 lbs zero oil consumption or problems but too early to tell
I rented a 386 Pete with the Paccar engine last year while my truck was in the shop for an engine rebuild. Engine had very little power but got about a mile to the gallon better fuel economy than my 06 Cat pre DPF engine in an 07 386 Pete. No issues with it but only used it for a couple of weeks.
My 2013 Cummins ISX 450 blew a head gasket at 55k miles. It made a huge bang that reverberated off the floorboard. Redding Freightliner handed it back to me the same afternoon, saying it was a loose coolant hose clamp. Bullsheviks! Even the T.A. techs in Corning knew it was the head gasket, but who believes them or the driver? I had a huge puddle under my truck the next morning. 23 agonizing days later i got my truck back. All Cummins-equipped tractors should come with earplugs. Noisy, especially when compared to the DDEC's. I wish the 12.7 Detroit was still made. Best lugger ever.
