Toyota231

Well i wasn't notified you had posted and just happen to be looking on here tonight, many months later and saw it, thanks to 5 months of 12 hours a day, 7 days a week at work i haven't had time to work on the darn truck. To answer your questions it happened pretty quickly, driver reported it one day, but then it was intermittent for the next week or so, maybe would do it once in a 10 hour day or a few times in a few hours, then i parked the truck. I never heard any grinding when i drove the truck and tried to replicate the problem while i was still running it, i will go back and check again as soon as i get a chance but if i try it now I am pretty sure there is no grinding, you can hear the shift from low to high, but of course no movement from the truck when the clutch is let out. Also i just happened to see it's kinda funny we aren't too far apart, I'm just up in Kernersville.

I'll give it a try when I get a chance but honestly I'm not sure that it's an air delivery issue. When the range is selected by the shifter you can hear the movement in the transmission pretty clearly shifting the range. Has a nice clunk noise either way. But I will check it out in hopes it's that simple, I know my luck though, it won't be.

2011 gu713 t310m. Driver reported it randomly wouldn't shift to high range, very intermittent. I only let him run a few days, it did it only a few times, but of course I couldn't replicate the condition. So I parked the truck for about 10 months, decided today before work to see if it did it for me, and it did, but now it won't shift into high range at all. Now I know this topic has been talked about, and I promise I searched, but my searching skills, wording things correctly to get proper results severely sucks. So I'm wandering what would you say is a usual culprit for said problem? How much of a chance it's just the air "solenoid" for the shifter or more likely the range selector/synchronizer in the trans. If it's the latter what does that job entail? I'm now actively trying to get the truck back going and get back into business and I'll be doing the work myself if I can get time in between my 12 hour, 7 day a week schedule at work(I have plenty of experience as a fleet mechanic just none on these transmissions). Just looking for some advice and a usual parts list on fixing it, while I'm at work I have time to sit down and see what I'm looking at to get the job done. Thanks, Justin

I understand how hard it is to diagnose over the internet, I'm not asking for a diagnosis, I'm asking for experience. What I mean by that is kind of an old school mechanic like me, someone that has been through a lot of diagnosis situations and remembers, "hey, I seen something similar to that one time, and this is what it was". But mostly in this situation I'm more curious on an explanation so I can understand the thought process. What I mean is, in my mind I can't wrap my mind around why the code could have been on for so long, will come back immediately after being cleared, why would it now be causing this problem, and even more so why would it cause a derate so constantly at only certain rpm's? Again not at all being argumentative, if there is reasoning behind it or if it's been seen before I will thoroughly listen, I know my questioning and reasoning is such a pain in the ass, I just genuinely want to use it as a learning situation where I can absord the info for my knowledge and learning and hopefully something I can pass on one day. I can't express how much I know to fix the code first, and should have already been fixed, but thanks to a severe neck and back injury I'm terribly limited on when and how I can do anything. Then on top of everything thanks to these awesome times we live in, in my area it is so hard to find a decent shop that isn't backed up for weeks, and most importantly has knowledgeable people. I don't mind paying twice what it costs to get a knowledgeable shop and person to diagnose and fix, but ill be damned if I pay a dime for someone to throw thousands in parts at a shot in the dark, that's exactly why I am so leary of local shops these days, I've found most are full of nothing but parts changers that couldn't do diagnostic work if their lives depended on it, then being a reasonably knowledgeable person with decades of experience on small diesel, automotive, and fabrication it just makes it worse, especially when I'm no longer able to do all the things I used to. Again I'm sorry my questions are such a pain, and i am such a pain, I just have one of those brains that never stops, that over analyzes everything.

Honestly I can't remember what software he has but I will check tomorrow, I know it is a professional grade equipment, he isn't some jack leg idiot, he is a very good mechanic that has been workeing in dealerships for years before going on his own, sadly Mack/Volvo is the least of his experience. But the one exact reason I am taking it to him is he will NOT just throw parts at it, he will diagnose, and the fact that i can go there and work to help take some burden off an up front bill right now helps me out greatly right now.

Per Mack the code does not lead to a turbo problem, it shows as a problem with either the sensor or wiring harness. The code has been on for over a month with no adverse effects on the truck so why now would it start causing a problem? The actuator was recalibrated and passed testing just a few weeks ago. The code does not come on or go off, it stays constant so why would it cause (or anything for that matter) a derate only at certain rpm's and not at others? Please don't take this as being argumentative, I am genuinely just trying to understand the reason you would think as you are, I'm seriously trying to absorb the information as future reference and a learning situation. I'm not at all ignorant to mechanics or trucks but I am admittingly severely under educated on the Mack/ Volvo engines (guess I should swap the order of those two but I would rather give Mack precedence over Volvo lol).

Let me say first I am not coming with a lot of information, I know this, but I'm just kinda hoping someone has seen this problem before and can lead me in a direction to begin. I haven't got the truck to a shop yet, mainly because I can't find a shop local to me that knows Mack's well enough for me to trust, and I can't afford the downtime at the wrong shop. Hopefully I can explain the problem clear enough to understand. Alright, a few days ago I'm hauling rock out of the quarry, first load goes fine. Second load I stop at a friends shop to chat. Go to leave and the problem presents itself. It happens in every gear, it does not clear up at any certain rpm but happens in the range of off idle up to around 1500 rpm. In that range the truck acts like it has 0 power, but when it reaches around 1500 rpm, it's like a switch is turned on and the power is there to the top of the rpm's. Truck idles fine, only code set is the turbo speed MID 128 PID 103 FMI 9. This code has been on for a while before this problem developed, and even after changing the sensor, I believe the code is a wiring problem I haven't been able to track down. Other than this problem the truck runs good, great oil pressure, fires right up, idles fine. I just bought the truck at 415,000 from a dealer and have no information on previous work or records. I'm getting the truck to a friends shop this weekend, he is a good mechanic but not much experience on a Mack especially the mp7 or mp7. Going to get the computer on it and see if anything shows. Again I'm just posting here in hopes someone has seen a similar problem and can give pointers. Winter and breakdowns have been rough, work is firing back up and I can't afford to miss any more time than needed, and dang sure can't afford to let someone work on it that's just going to throw parts at it till it's fixed, so maybe I'll get lucky with experienced advice. I hope to have it at my buddies shop and on the computer tomorrow afternoon or Sunday so I'll report back with any info from the computer diagnostics.