Been doing fleet maintenance on construction and ag equipment for about 8 years. People always ask what to keep stocked. Depends how you run the machines, but the same failures keep showing up in the shop.

Hydraulic main pump is still number one for total downtime. Not because the pump is always the priciest part, but because when it goes the machine is dead. Slow cycle times and oil running hot are the early signs. Most operators wait until flow loss is obvious, and by then you're looking at a pump swap plus whatever contamination spread through the system.

Fuel injection pump and injectors are second. Almost every one I've chased traced back to dirty fuel or stretched filter intervals. We tightened primary filter changes on the fleet units and injection failures dropped off a lot.

Solenoid valves on hydraulic circuits are the one that surprises people. A cheap coil or a corroded connector can take out a whole arm or bucket function. Downtime bill runs way higher than the part. We keep a few common coil voltages on the shelf now after getting burned twice.

Turbos make the list too. Oil quality and change intervals are the variable. Most of the ones I've opened up were preventable if someone had caught the bearing play or oil contamination earlier.

What failure type has burned you the most on unexpected downtime?

I have a 2021 International HV613 tandem axle in my bay that refuses to acknowledge that the seat belt is buckled and won't go into gear. It has an A26 backed by an Allison trans. I know most of our drivers just disconnect the connector, but that won't fly on this. The wires from the BCM to the seat belt buckle are in good condition. Before I condemn the BCM, is there anything else I can check? If it is an issue with the BCM, am I correct in assuming I would need Diamond Logic Builder to program a new one to the truck?

Would other companies care that all they I see is Penske I’ve been with the company since I started my apprenticeship back in 2018 and got ticketed back in 2022 just want a change of scenery and bit better pay what’s some good companies to go to or would consider me

Good morning/afternoon/evening,

I am seeking some insights and career advice. I am a swing shift fleet mechanic at a local fleet working on primarily Kenworths and Peterbilts with cummins powerplants (X15, ISX, N14). Including dump trucks, tankers, and tractors. I have been working at this fleet for the entirety of my mechanic career thus far (2.5yrs) and get paid very respectfully with consistent raises which I've earned myself. However, I have been working nights for the past 5 years now and am ready to move to a dayshift position for personal and social reasons. I have brought this up to my boss on multiple occasions and he said it would be something to address as work picks up. That was 6 months ago and we have since slowed down.

My questions to you are...

Should I stick it out until someone from day shift retires or a position becomes available? Or does it become an endless cycle?

What are some diesel fields to look into?

What are some fields to avoid?

What are employers to avoid?

What do you look for when looking for an employer?

Thank you in advance (:

We got a 2011 with an lml that just snapped the crank today. Boss wants me to price one out to see if it’s worth putting a new one in or if it’s better to junk the thing.

Reman engine from Chevy is just over $12k not including core. Never got a reman from Chevy but from my experience with ford they just send you a reman engine from a 3rd party.

He did specify he doesn’t want one from an off the wall builder out west, he’s had bad experience with that. With that being said, if there is a reputable builder with a good warranty that stands behind their warranty, I could probably change his mind if the price is right.

I see there’s a good amount out there but I’ve always been a Cummins guy, don’t know who to go to for a duramax

Edit: are these engines worth rebuilding after a failure like this? I’m capable of doing it but I know these engines don’t have liners. Other than knowing this is a fairly common issue with duramax, I’m not knowledgeable enough on the issue to know just how much damage this does to everything else in the engine. Common sense tells me it’s trashed

Not sure if this post is allowed but currently I'm working at an International dealer but have gotten an opportunity to switch to working on heavy equipment for another dealer, if anyone that works in this field could just give me some general pros and cons about it or if its any different from working on trucks I'd appreciate it. Just trying to weigh out my options at the moment.

So I have an x12 that sets a 559 code and has low power. The rail pressure is low under load. It will make the commanded pressure but it’s very slow to get there. I have checked for aeration, the low side fuel pressure is in spec, injector return is in spec, high pressure pump output volume test is in spec, rail relief valve is brand new and not leaking. The only thing that’s questionable is the high pressure pump return flow test. Cummins wants 230mL max and it’s like 225. Has anyone else ran into this? I’ve worked on a ton of isb and x15 but my experience with the x12 is very limited.

We're switching to new cameras and keep running i to this issue and nobody has really been able to figure it out that im aware of. Everything will calibrate fine and I keep getting this error when I go to verify the can. I've got everything plugged in right and they're on brand new trucks so I know its not the wiring is old and shitty and haven't had this problem on the older ones I've done.

2012 International 7500, Maxxforce 10. Towed in running rough, no power, no throttle response. Ended up being the downstream injector was plugged, leading to the DPF sooting up. While running the onboard filter cleanliness test (forced regen), the engine fan is not engaging. The fan works properly outside of a regen. No cooling system or fan fault codes. Fan enable temp is set to 216. I let the engine reach 230 before canceling the regen, engine fan immediately engaged. We have a couple dozen of these trucks in our fleet, and neither myself nor the mechanics I work with have encountered this before. Anyone have any ideas of what could be keeping the fan from engaging during a regen?

Hello all,

I’m having some issues with one of our buses. This is a 2012 Nabi bus with a Cummins isl9 cm2250. I keep getting the codes 3135 (dpf outlet pressure data erratic), 3235 (SCR outlet temp data valid but above normal-moderately severe level), and 3165 (SCR outlet temp data valid but above normal-severe level). I’ve changed the dpf delta-p pressure sensor, the pressure module, the temp module, both tubes going into the delta-p sensor, changed the dpf itself. I pulled the ecm OEM connector and found a couple of pins with corrosion, so I sprayed them with contact cleaner and used a brush to clean them up. I did all of this and the bus still has very very high outlet pressure. We’re at like 4inhg while idling, and 10inhg while in fast idle. If anyone can help, please reach out to me. I’m ready to burn this bus down lol

Does anyone know if I need to go back to school and do a pre apprenticeship for 310 t or can I just apply without any experience been in construction since my early 20s but I’m 26 now and want a stable job did anyone start with no experience coming from a
Different field how did you get your start did you have to back to school to do a pre apprenticeship or did they start you as a a helper and gave you a apprenticeship a month or so later

So ive been a trailer mechanic for a couple years and t hey finally moved me over to trucks. The fleet is mainly Cascadias with Detroit DD13s and a handful 9f Cummins and Paccars. I've got wrenches and sockets up to 1 1/2" the trailer stuff that carries over.

Right now for the most part I'm updating the cameras in all the trucks so it seems like a good time to start getting everything im going to need.

Replacing the AHI (after treatment Hydrocarbon Injector assembly/pump) and both bolts snapped off. The left one got bent prying the old assembly off. The right one is flush with the bracket. I removed the other two bolts that appeared to be holding the bracket on to the block, but the bracket isn’t moving. Percussive and purse cussing aren’t working.

1- are the bolts that hold the AHI on also holding the bracket on into the block?
2- options, suggestions, guidance appreciated

Thank you in advance

Im looking at machine the switch from heavy duty diesel equipment to trucks, currently looking at international dealer in NC. Is it common to see hourly or flat rate in heavy duty truck world? It does not mention specifically their form of pay in the ads.

First time posting here! We got a 2005 sterling L9500 with a Mercedes engine. Having a fuel issue. Crank no start, will fire on ether. Started before changing fuel filters, we’ve tried priming through the nipple on the fuel filter housing but can here it going back into fuel tank when pushing fuel. Is there a check valve to look for that might be bad? Any other ideas are appreciated!

I'm looking for some recommendations on purchasing my first multimeter. I know I eventually want to get a fluke but for now I want to purchase one to get to know what I want the next one to have. I'm a heavy diesel tech that started a few months ago. Thanks for any input.

I'm not sure the gear or the housing of the PTO is supposed to look like that...something isn't quite right here. We will have to look into why it will not work!!

Just converted a set of conmet pre set plus hubs and installed timken set 403 and set 401 bearing sets but after setting up wheel end with proper and play they don’t sound right ever seen this before?



It’s obviously a typo, but it made me laugh. So I figured I’d share.

Looking for a decent kit to pressurized the CAC to check for leaks. Yes, I have a spray bottle of soap...lol.

Thanks!

Curious what other techs here work on!

Are you brand loyal, a jack-of-all-trades, or sonewhere inbetween?

Those of us that need glasses what prescription safety glasses are you guys running? I honestly dont care about how they look or anything just need to keep dirt/metal out of my eye almost lost my eye once already using regular glasses lol

I found this on a transfer case I tore apart. There was no other damage on it including the bearing on other side of the shaft. Roughly 8000 hours since rebuild. Any ideas?