New Truck - X15 Advice

[Camstyn]

So I’m running out of warranty on my 2014 Peterbilt 579 in a couple weeks, and the aftertreatment has been non stop headaches for the past 4 months. One CEL after the other. It’s still a good truck, has less than 500,000 miles on it and the engine itself appears to be in good shape after recent leakdown/compression tests. 500hp MX13, by the way.

I do not see owning this truck off warranty as a good option unless I de-mandate it. I’m hesitant to do that either though simply because it’s a MX rather than an ISX and I’m concerned about who’s going to work on it after it’s been tampered with. My dealer flat out told me that they can do general servicing on it but it’s never going to get hooked up to their computer for diagnosing/troubleshooting if I choose to do this.

That being said, my other option is to just trade it in on a new one. I can take one with a 565, or I can order one with a 500 Efficiency series.

My question is, what would you guys suggest? Is the efficiency a better engine than the performance series? Can the 565 be as efficient as the 500 if it’s driven nicely, or turned down to 505?

Application will be hauling light van loads (courier freight in the kootenays, so lots of twisty and steep mountain driving. The MX gets about 6.5mpg doing this work snd I don’t want to see it get any worse, within reason. I’ve gotten the same numbers even using long hood Petes with 625 Acert’s doing this run. The only trucks that have done better were my 03 Western Star with a 12.7 Detroit and a POS Maxxfart that I had to rent one night.