Diesel & Engine Repair

Your engine is the most expensive thing on the truck to get wrong — which is exactly why guessing costs you so much. When a shop swaps parts on a hunch, you pay for the wrong fix and the breakdown that follows. J&A Fleet doesn’t work that way. We run real diagnostics, find the root of the problem, and fix that — whether it’s a sensor, a fuel issue, or a tired engine that needs a rebuild. Caterpillar Level 2 certified techs, mobile when the job allows, in the shop when it needs the bay.

WHAT WE DIAGNOSE AND REPAIR

  • Hard starts, no-starts, and rough running
  • Power loss, derates, and limp-mode faults
  • Check-engine and warning lights — read, traced, and explained
  • Fuel system problems — injectors, pumps, lines, and water-in-fuel
  • Turbo and boost issues
  • Aftertreatment and emissions — DPF, DEF, and regen faults
  • Coolant and oil leaks, overheating tied to engine condition
  • Major work — head gaskets, in-frame and out-of-frame rebuilds, and full engine replacement

HOW WE DIAGNOSE — AND WHY IT SAVES YOU MONEY

A warning light is a starting point, not an answer. We confirm the actual fault before we quote a repair, because the codes don’t always tell the whole story. If we can’t recreate the problem, we keep digging — we won’t bill you for parts that “might” fix it. When we know what’s wrong, we tell you what it’ll take, what it’ll cost, and whether the repair is even worth it on that truck. That honest call has saved customers from dumping money into a unit that wasn’t worth saving — and saved others thousands over what another shop wanted for a part they didn’t need.

DONE RIGHT THE FIRST TIME

Our techs are trained on heavy-duty diesel and certified to work on it. We use quality parts, torque to spec, and verify the fix before the truck leaves — because a comeback costs you another day down, and that’s the opposite of the point. Whether it’s a quick diagnostic or a full overhaul, the standard is the same: fixed right, once.

PRICING YOU CAN SEE COMING

You’ll hear our hourly rate, our minimum, and any surcharges up front. Mobile road service is billed port to port — from when we leave the shop to when we return — and the price only changes if the job changes. No padded estimates, no surprise line items.

MOBILE OR IN THE SHOP

A lot of diesel work can be handled on site, and we’ll come to you for it. For bigger jobs — rebuilds, replacements, anything needing the bay — we don’t run tow trucks, but we work with a network of tow companies and get the best rates to bring your truck in, then handle the repair once it’s here.

WHERE WE WORK

Diesel and engine repair across Morris, Aurora, Joliet, New Lenox, Rockdale, Gardner, and the surrounding I-80 / I-55 corridor.

What Our Customer Says

Went to a chain that wanted over $3,000 for a part we didn’t need. J&A found the actual problem and had us ready to go in under an hour. Very honest shop.

WHY Choose J&A Fleet

Founded by a diesel tech who became a fleet manager and got tired of watching shops sell labor instead of fixing trucks. That’s the whole reason J&A exists — honest diagnosis, fair pricing, and engine work that holds up.

Engine acting up?

Don’t wait for it to strand you. Call J&A Fleet at (815) 518-5252 for diesel and engine repair done right.

Truck Down? Call Now.

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Our Happy Clients

ermias kassahun
Excellent service and very honest people. I came in with a driveshaft/carrier bearing issue causing vibration on my truck, and they stayed after hours to help me. Small family-owned shop with great courtesy, professionalism, and customer service. They explained the issue, showed me the work, and made sure everything was done properly. I’m very satisfied with the repair and thankful for their help. Highly recommend this shop for driveline and truck repairs.
Braden Munoz
These guys were awesome, needed a quick hose fix, I was in and out in 10 min and they were super nice people. Would highly recommend to anyone!
James Rutherford III
Thanks again John and Charlie for getting me back up and running the next morning. Your tow truck driver was friendly and professional and towed me to your shop and dropped me at the hotel and your guy Charlie had me fixed and on the road 5 mins before check out at the hotel.Will save your number if I ever break down again in your area.
John Carroll
John with J&A Fleet was awakened in the middle of the night. I waited less than 15 minutes for his arrival. He had me up and running within seconds. Showed me some unique tricks for future issues. You cannot go wrong with folks like John. Thank you so very much for making a difficult time seem so easy. Will not forget.
RFS Billing
Went to TA and they were going to charge over 3 k said we needed a 5th wheel plate. J&A techs found the actual problem and had us ready to go in less than an hour. Very honest shop
Nam Phamtran
Talked to John about paying for him to inspect a truck, I told him the specs on the truck and he told me over the phone that it was not worth the money that they were asking for the truck. He was honest even though he would be losing out on the inspection fees. What a great guy and company!
Adam Ryder
John and the entire J&A team are very easy to work with. They get the job done right and in a timely manner. We will definitely be using them again!
Shon Thomas
Awesome guys did great job far price put a lot work in to fixing my trailer finished fairly quick would highly recommend using these guy's
Carthon Diggs
Simply the best & efficient. They are good at diagnosing whatever problem you have. Pricing is very straightforward. Will definitely use this place again
Kenneth Cotter
Some of the best people at work here. If you need anything done, come here and they’ll get you sorted out. 10/10.
Marcus Haynes
Quick fast knowledgeable and efficient. I had issues with my 2027 Volvo 860 and in minutes he got me running perfect again. Thank you so much
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