Pullin with the dreaded PACCAR Mx13

Those cab shocks always rust. They're like $100 apiece. I think you got a pretty good truck to start out with and a lot of the MX13 hate is a little bit the typical "Ford vs Chevy" stuff where somebody has a bad experience (or a great one) with one or the other and thinks they're all that way. Hang around the internet long enough and you'll have 12 different opinions from 10 different people. All you can do is treat it as right as you can as far as regular PMs, no cheap parts, stay away from shops you don't get a solid impression from, and don't idle it unless its an extreme weather situation.

Shopping for the perfect used truck is about like shopping for the perfect wife. In other words they don't exist.

 

I wouldn’t swap tires. My ‘22 had the 12 spd with 2.79 rears and it was perfect for running 68-ish. Around 1300 RPM right where it needs to be. At the speed you said you want to run going to larger tires would have the trans shifting between 11 and 12 all the time.

 

Looks nice. Good luck with it. Never had any experience with those so don’t really have an opinion.

 

I am realizing that the Paccar MX13 has issues when hauling heavier loads over 38k lbs on steep hill type terrain. I've been refusing heavier loads in order of not being in the shop with a check engine light even after a recent DPF cleaned and all new injectors back in May. Issue after issue besides the freight market which seems to be improving but always comes down to the Paccar without issues now not covered by warranty. This video speaks volumes and when meeting others in the garages whiles their waiting for their trucks 8 out of 10 at Peterbilt dealerships have the same engine in their truck at any given Pererbilt dealership in any state or province. Coincidences can't occur that much in one year and their hasn't been a month yet I didn't have to go into the garage for something. Maybe for some they believe it only has minor issues oppose to major but I've personally never seen a motor in my 30 plus years of driving seen this much problems. When purchasing back in 2022 I should of gone with my instincts of not knowing much about the Paccar engine. My recommendations for anyone who's stuck with one is not to idle the motor at all if they can help it and be sure to change the oil regularly before 12,500 miles even though online it says 40,000 mile oil change intervals. I am starting to believe with the biodiesel is a major issue for the paccar motors and I've been trying to avoid it when ever possible but it's been difficult regarding most major fuel suppliers supplying biodiesel.

 

Good job getting a truck and getting started. Place I used to lease to changed from Cummins to pacar motors in 2019. Best decision he ever made, he claims.

 

This is pretty much inline with my experinces. I found at about 10-12K is where my samples always said the oil was shot when i had them tested regardless of if i used full synthetic or convention.
i also found popping a new filter on every 5 to 6k miles helped a lot.

 

I must be extremely lucky to have driven 3 of them with none of the problems you talk about. The 2017 I had originally ran the northwest at 105k and the current owner put a lift axle back on it and is hauling milk on 7 axles. I’ve never owned an APU on any truck and I idled to stay cool and when it was single digits and colder. On the two I owned I followed the service schedule of the guy I currently drive for. Change filters at 20k, oil and filters at 40k. Dumping oil at 12k is wasting money if you’re running a 10-30 synthetic.

 

Nah, that would make the overall gearing worse. I hate the 2.79 rear ends in mine. Makes overdrive too laggy/luggy. 65 MPH it’s lugging along at 1250 rpm. Have to get it up to 70 to get up to a more comfy and smooth running 1350 but 70 is a little fast unless you’re really out in the wide open stuff.

I’d rather it was running 1350 at 65 personally and I would spend a lot less time babysitting the autoshifting transmission. Most of these trucks of course are tuned for MPG and not performance so it always wants to be in the highest gear possible not matter how inappropriate it might be for the driving situation. (I almost miss the good ole days where the transmission stayed in whatever gear you shoved the stick into lol.)

 

I’m the opposite. I had no issue running 65-ish with 2.79’s. I wanted 2.64 when I ordered it but they wouldn’t do them with the 510/1850 engine. I also spent time with the computer guy at the dealer after I had my truck about 3 weeks and for a few hours we went over all the settings for the transmission and made changes based on my likes and dislikes.

 

More powerful engine might have made that fine in your case. Kind of depends on how and where you drive and what you haul. I prefer using slightly higher RPMs and more torque multiplication from the gearing rather than extra horsepower. Horsepower is nice to have too of course but it uses fuel and makes heat.