steeler

I ran across one like that, hollowed out, but not deleted.... Go figure lol

Same here. We have customers that run 80 90 without issues in them, but unless the customer requests otherwise, we fill all rebuilds with 50w synthetic.

Yours doesn't have a check engine light, just the lightning bolt and red shut down light. You can get the lightning bolt to blink any active codes for you by turning cruise off, then hold down (I think it's down?) the set/decel switch until the light starts blinking a 2 digit number...

You probably won't have much luck locking the range cylinder in by hand. It takes a decent amount of pressure. But if your problem isn't with the cylinder/stuck piston, then you'll be removing the auxiliary section anyway. Assuming it isn't an air pressure problem.

The larger piston is your range cylinder, smaller is reduction. In high range the large piston will be pushed towards the front of the transmission, to the rear for low. Like Joey said, you can remove that whole range housing by removing the air lines, 5 bolts and 2 nuts on the pistons. The shift forks will stay in the transmission and won't go anywhere. They make a kit with gaskets and o rings to service the housing.

Was there any gunk/rust in that deep reduction cylinder? I've seen many that are rusted up and not used often, then when they get used they stick and have your exact issue... I've built 100's of 8ll's. I could almost do one blindfolded lol. No joke

I think it was around 10k in Volvos pocket!

Just a final update. Almost a month later and no problems, so...... Aftermarket Dpf, was the culprit. For whatever reason, this truck did not like it and wanted the big $$ oem!

Probably coincidence. Couldn't tell you how many cam failures I've done and found an eup with the dangling spring. H ring/lifter failure had nothing to do with the eup coming apart imo.

Lol if it can happen, it'll happen to me! Had an mp today that would only run for 10 seconds then shut off, losing communication from engine ecu. Turned out it was a leaking freeze plug in the turbo, behind the vgt actuator. Coolant had leaked in between turbo and actuator, getting inside actuator and shorting out, causing the ecu to go dead. That was a first for me. As far as my original post, I don't want to jinx myself but 2 days in and so far the truck is doing fine. Fingers crossed that it just didn't like the aftermarket Dpf!

Yeah, going to release it to the customer and let them run it and see what we've got. I'll post the result in a few days!

Ok, went with oem filter, test drove same route as before. Probably 50 miles. Soot level with oem filter went from 5 to 31 after drive. With aftermarket filter I went from 0 soot to 77...... Big difference

It does not look plugged as I would normally see with an engine issue. I can shine I light right thru the doc and the Dpf isn't black on the face. After I replaced the Dpf, truck came back 3 days later with the frequent regen so we sent the Dpf out to have it checked and they said it was clogged, although I couldn't see anything visually. I'm throwing an oem Dpf on it now, just to see if the truck doesn't like aftermarket. I've run into that with Cummins a few times where the truck wouldn't like aftermarket, but worked perfect with oem. Never seen it with Mack/Volvo though.

I did not replace the pm sensor. The problem is more of the Dpf differential pressure rising to fast from either clogging at a very fast rate, or a filter problem.

Well, injectors were a parts Canon whiff! Took it for a 40 mile test drive and went from 0% soot to 73%. Checked to make sure aftertreatment fuel was actually shutting off to 7th injector, which it is. No egr codes but ran egr test and appears to be closing 100% Pulled turbo outlet, didnt appear to have excessive smoke, 1 little puff of black when you first mashed the throttle, then clear. I drove it with turbo outlet off and did not see any smoke trailing behind. I'm beginning to wonder about the Dpf filter. We put a recored one in it from a company that cleans/recores here locally. So it's not an oem new filter. BUT, I'd be looking at the parts cannon again for 3 grand to try an oem filter. Just not sure what to toss next.

And I appreciate you! After treatment fuel pressure is 65. All the numbers during regen look great, but something is causing it to soot up pretty quick while driving.

I did check ports and they are clear. Customer wants to go ahead and throw a set of injectors at it. I'm skeptical... I've seen bag injectors cause funky regents, but I haven't seen them cause frequent regen. Not on a mack anyway. I did run into that with a Cummins.

Hey all, I normally don't run into something like this that isn't fairly easy to diagnose... But I'm working on a 2018 mp8 that needs parked regen daily. Originally came in shop with whacky exhaust temps during regen. Dpf filter was junk. Replaced filter and new 1 box. Exhaust temps during regen look great, soot drops to 0, but rises quickly during the day. I replaced the Dpf diff pressure sensor and all temp sensors during this process. Engine runs great. Vgt sweep is good, egr cooler not leaking. No exhaust or boost leaks. A little stumped!

What Joe said. I've seen bad grounds, weak connections cause this very issue. During cranking voltage can drop too low to start.

Exhaust temp is not high enough, and 260 degrees before cat? That can't be right.. When I have whacky exhaust temps I'm looking at 7th injector, face plugged cat, temp sensors...

Id almost bet a paycheck its cups..

Doozy here, as normal for me. 2016 mp7 overheating in a pull, or during regen. Engine fan will not engage at all for coolant temp, but will for air conditioning pressure, and manually with tech tool. New fan drive, ecu and vcu. Customer had replaced water pump, thermostat, fan drive before bringing it to me. Didn't take long to determine the fan is not speeding up with coolant temp, but appears to work fine with other signals...

I'm still here, but damn that was 4 years ago. I'm trying to jar my memory as to what I did to fix it. I've had so many cluster f jobs since then they all run together. I wasn't keeping very good notes back then. I'll keep thinking!!

Little late to the party here but looks like you're ecu isn't powering up. I usually find that it's missing power or ground. I'd check that first, if you haven't already fixed it. I'm not at work to look up which pins are power and ground right now, but can get that info to you if you need it.

Thanks guys. It can be hard to find good info, or people to bounce ideas off of. There is a lot of good knowledge on this site, if I can contribute and save someone a giant headache I'm all for it! A lot of people think that they have to go to a dealership to get good service, totally false! I worked at a mack dealership, plenty of clowns there just like anywhere else 😂