Question 1

How often should I change the oil in my diesel?

Accepted Answer

It depends on how you use the truck. Under normal driving, many newer common-rail diesels can go 7,500–10,000 miles. But if you tow, idle a lot, run stop-and-go, or drive an older engine, you're in "severe use" — and 5,000 miles (or sooner) is smarter. When in doubt, we'll help you set an interval based on how your truck actually works for a living.

Question 2

How often should I change my fuel filter(s)?

Accepted Answer

A common interval is around every 10,000 miles, though factory recommendations vary by truck. Diesel fuel carries more water and contaminants than gas, so a clean filter is cheap insurance against very expensive injector and fuel-pump damage. We keep OEM filters in stock, so it's a quick service.

Question 3

Does towing or heavy use change my maintenance schedule?

Accepted Answer

Yes. Heavy towing, hauling, frequent idling, and extreme heat all count as severe-duty use and shorten your intervals — oil, transmission fluid, and differential fluid all wear faster under load. If you tow regularly, tell us, and we'll build a schedule around it.

Question 4

What maintenance do people overlook on a diesel?

Accepted Answer

The big ones are differential (gear) oil, coolant condition, brake fluid, and on 4WD trucks the transfer case fluid. They're easy to overlook because they're "out of sight," but neglecting them leads to expensive surprises down the road.

Question 5

Do you work on all three — Ford, Dodge, and Chevy diesels?

Accepted Answer

Yes. We specialize in Ford Light Duty PowerStroke and have many years of experience with Dodge Cummins and Chevy Duramax repairs — bumper to bumper.

Question 6

Do you only work on diesel trucks?

Accepted Answer

No. Diesel is our specialty, but we do general automotive and engine work too — gas trucks, UTVs, and more. As our customers put it, there's no job too big or too small.

Question 7

Will you try to sell me work I don't actually need?

Accepted Answer

No. We diagnose carefully, tell you what's actually wrong, and give you a heads-up on what might need attention down the road — without pressure. We'd rather earn a customer for life than push a sale.

Question 8

I put the wrong fuel — or DEF — in my diesel tank. Can you fix it?

Accepted Answer

Yes. Misfueling (including DEF in the diesel tank) can require a fuel system cleanout or rebuild, and we've handled it. In some cases it may even be covered by insurance — and we can help you work through that process.

Question 9

Do you service commercial fleets?

Accepted Answer

Yes. We keep a number of local fleets running and can work with you on turnaround and scheduling to keep your trucks earning.

Question 10

What is a DPF regen, and why does my truck do it?

Accepted Answer

Your diesel particulate filter (DPF) traps soot from the exhaust, and "regen" is the process that burns that soot off. On the highway it often happens on its own (passive). When it can't, the truck raises exhaust temperature on its own (active), and if that fails, it needs a parked/forced regen with a shop's diagnostic tools. A regen here and there is completely normal.

Question 11

Why does my truck keep regenerating so often?

Accepted Answer

Frequent regens usually mean something else is wrong — short trips and heavy idling that never let the filter finish cleaning, or a deeper issue like a bad sensor, a boost leak, leaking injectors, or an EGR problem making extra soot. The filter often gets blamed first, but it's not always the real cause. We diagnose the source instead of just throwing a filter at it.

Question 12

My DPF light is flashing or my truck dropped into reduced power — what do I do?

Accepted Answer

Don't push through it. A flashing DPF light or an engine "derate" means the system is near its limit, and continued driving can lead to a shutdown or major damage. Get it to us so we can scan it, run the data, and clear the root cause safely.

Question 13

My check engine light is on — is it safe to drive?

Accepted Answer

Sometimes yes, sometimes no — and the light alone doesn't tell you which. We pull the codes, read the live data, and find out what's actually happening before recommending anything. No guessing, no throwing parts at it.

Question 14

Do you handle emissions diagnosis and DPF service?

Accepted Answer

Yes — DPF service, emissions diagnosis, and the careful diagnosis that goes with them are core to what we do. We track emissions faults to their real cause rather than chasing codes.

Question 15

Do you work on the 6.0L PowerStroke — and can you "bulletproof" mine?

Accepted Answer

Yes — the 6.0L is one of our specialties, and it's a truck a lot of other shops won't touch. Whether you've got a no-start, a hard-start when hot, injector trouble, or you want it bulletproofed for long-term reliability, that's right in our wheelhouse.

Question 16

My truck cranks but won't start, or only acts up when it's hot — can you figure it out?

Accepted Answer

That's exactly the kind of intermittent gremlin we diagnose every day. Hard-starting and heat-related no-starts on diesels can come from several sources, so we read the data and find the real cause instead of guessing.

Question 17

How do I know if I need a transmission service or a full rebuild?

Accepted Answer

That's exactly what a proper diagnosis tells you — and it's why we diagnose first. Plenty of "my transmission is failing" trucks just need a fluid service and a shift kit. We won't sell you a rebuild you don't need.

Question 18

How often should diesel transmission fluid be serviced?

Accepted Answer

It varies by truck and how hard you work it, but towing and heavy loads shorten the interval. If your truck tows a fifth wheel or hauls regularly, service it more often — heat is what kills a transmission. We'll set the right interval for your usage.

Question 19

My transmission is slipping or shifting hard — what now?

Accepted Answer

Slipping, harsh or delayed shifts, or a burnt smell are early warnings worth catching before they turn into a rebuild. Bring it in and we'll diagnose the cause — automatic or manual.

Question 20

I feel a vibration or hear a clunk — what's causing it?

Accepted Answer

It could be a U-joint, wheel bearing, worn bushing, driveshaft, or a few other things — and it doesn't always come from where you'd expect. We track down the actual source before replacing anything, so you fix the real problem the first time.

Question 21

Can you set my truck up for towing?

Accepted Answer

Yes — hitch installation (including gooseneck and 5th wheel), trailer wiring, and trailer brake controller setup are all in our wheelhouse, along with auxiliary and LED lighting.

Question 22

Do you fix electrical problems and wiring gremlins?

Accepted Answer

We do. Diesel trucks rack up miles of vibration that can chafe wiring and cause intermittent electrical issues. We handle electrical diagnosis, wiring and connector repair, and accessory wiring.

Question 23

Should I get a used diesel inspected before I buy it?

Accepted Answer

Absolutely. A used diesel can hide expensive problems — emissions components, injectors, transmission condition, frame rust, and trouble codes that aren't even triggering a check engine light. A pre-purchase inspection from a diesel specialist can save you from a money pit.

Question 24

What is a digital inspection?

Accepted Answer

Instead of a verbal "looks fine," you get a clear, itemized report sent straight to your phone — with photos of exactly what we found. You see the truck's real condition for yourself, not just our word for it.

Question 25

What do you check on a pre-purchase digital inspection?

Accepted Answer

We go over the truck bumper to bumper — engine and emissions system, transmission and driveline, suspension, brakes, leaks, and overall condition — and send you the photos and findings so you know what you're buying before you sign.

Question 26

What are OEM parts?

Accepted Answer

Original Equipment Manufacturer parts. We get them directly from the vehicle dealership — they're the exact same parts that were on your vehicle when you bought it.

Question 27

What warranty do you offer?

Accepted Answer

OEM parts are backed by a 2-year / unlimited-mile warranty. NAPA parts are covered by the NAPA 12-month / 12,000-mile warranty.

Question 28

Do you use OEM parts?

Accepted Answer

Yes — OEM parts only, and we keep a large parts inventory plus OEM filters in stock to cut your downtime.

MAD TECH —

DIESEL WORKZ

» Digital Inspections Now Available

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