A truck that will not stay in gear, that grinds on a shift, or that dumps a pan of glittered oil is not a “keep driving it” problem. KG Truck Services diagnoses, repairs, and rebuilds heavy-duty transmissions in Mississauga for owner-operators and fleets running Eaton Fuller manuals, Allison automatics, and Volvo and Mack gearboxes. The goal is the same on every job: find the failed component, fix the cause — clutch, cooler, electronics, or the box itself — and put the truck back in a gear it will hold.
Manual transmissions and clutch work
Eaton Fuller 9-, 10-, 13-, and 18-speeds are still the backbone of a lot of Canadian highway and dump work. We service range and splitter issues, worn shift forks, bearings, input shafts, and auxiliary sections. A hard shift is not automatically a transmission failure. Clutch brake timing, a worn clutch, a failing air line to the range piston, or a shift tower bushing can mimic a dying gearbox. We inspect the clutch and linkage before we quote a rebuild, because pulling a transmission that did not need to come out is how invoices get unjustifiable.
When the box does need to come down, we inspect gears, synchronizers where fitted, bearings, and the case. Rebuilds get new wear components, the correct lube, and a check of the yoke and output seal so you are not back in a week with a leak on the output. We also look upstream and downstream. An engine that is out of time or a driveline with a bad U-joint will destroy a fresh transmission. If we see that, it goes on the work order before we button the truck up.
Allison automatics and electronic controls
Allison transmissions in vocational trucks — refuse, mixer, plow, yard tractor — fail differently. Overheat from a plugged cooler, contaminated fluid from a neglected filter, solenoid and TCM faults, and worn lockup clutches are the usual story. We scan the TCM, check line pressure and fluid condition, and pressure-test coolers. A pan full of friction material is a rebuild conversation. A code for a speed sensor might be a $200 repair. Guessing which one you have from the parking lot is how automatic jobs go wrong.
Volvo I-Shift and Mack mDrive units sit in the middle: they are automated manuals with clutch actuators, position sensors, and software that will refuse to shift if a sensor is out of range. We treat those as a diagnostics job first. Sometimes the clutch needs replacing. Sometimes the transmission needs a rebuild. Sometimes the ECU needs a calibration after related engine work. Electronic diagnostics is a core KG specialty, so these trucks stay in-house instead of bouncing between a gearbox shop and a dealer programmer.
Road test, then release
A transmission repair is not done when the last bolt is torqued. We check for leaks, confirm shift quality, and road-test where the complaint can actually show up — not just around the block in first gear. If the truck came in with a related differential noise or a driveline vibration, we flag it. Those systems share the torque path, and ignoring them is how a “rebuilt trans” comes back.
We work on Freightliner, Peterbilt, Kenworth, Volvo, Mack, International, and Western Star chassis at 6771 Columbus Road. If the truck is down in a yard, ask about mobile diagnosis to confirm whether it needs a tow. For a quote or a bay, call (905) 564-0880.
