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Automotive HD/Fleet Forum

Professional automotive forum for discussion of heavy-duty trucks, buses and other on- and off-road equipment, and maintenance of automotive fleet vehicles. Discussion topics include fuels and lubricants, hydraulics, performance, on-board diagnostics, powertrain, power distribution, anti-lock braking and stability control systems, and best practices as they relate to heavy duty and fleet maintenance. This forum is for experienced automotive repair professionals only, membership required.

Continue to the description of our next automotive discussion forum, the HVAC Forum.

Recent Automotive Discussions in the Automotive HD/Fleet Forum

Cummins 3225 fault code
08/19/2025 in the HD/Fleet Forum
[Driveability: 15 Kenworth T680 14.9L] Hello HD fans, Been dealing with this 3225 fault code for awhile. It's for air purge valve mechanical issues. Working on Cummins ISX15 with 560K miles. I have replace the air purge valve, fuel shut-off valve, doser ...
Turbo Actuator
08/14/2025 in the HD/Fleet Forum
[Driveability: 15 Ram 3500 Laramie 6.7L] Apparently a company in Decatur, Alabama -City Diesel-makes a replacement turbo actuator that doesn't have to be programmed, it is automatic. Has anyone used one of these? Or , they also sell the whole turbo with ...
Parts/Tools
08/13/2025 in the HD/Fleet Forum
I will be retiring in a couple weeks. We were a Cummins midrange dealer for 35 years and a Ford Dealer until 1998. They are shutting the truck dep't down after i leave so we have a bunch of parts and tooling we are selling. I have a usb drive of the Cummi...
2001 Mack MR Idle Up Issues With Leach Packer Body 2RII
08/13/2025 in the HD/Fleet Forum
[Electrical: 02 Mack MR MR600K] Have this unit that came in, municipality garbage truck. Their own mechanic worked on it and messed with all the wiring under the dash for the idle up system. Truck originally came in for idling high with no fuel pedal res...
Air bag suspension issues
08/07/2025 in the HD/Fleet Forum
[Chassis: 07 Sterling Truck A9500 11.1L] This truck has air bag/air suspension problems. It has a 4 air bags/springs in the rear 2 per axle. The Driver side front axle was bad/broken, seems like the bottom part of it-the plastic housing that sits on the ...

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