Heavy Duty Transmission & Clutch Repair
From complex diagnostics on automated manuals to complete overhauls on classic 18-speeds, CTR is Concord's trusted source for transmission and clutch repair. We get your truck's powertrain running flawlessly to minimize downtime and maximize reliability.
The Expertise Your Drivetrain Demands
A transmission failure brings your operation to a halt. We combine 30+ years of hands-on experience with OEM-level diagnostic tools to provide repairs that last, backed by a 3-year/36,000-mile warranty.
All Major Platforms Under One Roof
Most independent shops specialize in one or two transmission brands. CTR services Eaton Fuller, Allison, Volvo I-Shift, Mack mDRIVE, Detroit DT12, Meritor, and ZF — with the OEM diagnostic software for each. If your fleet runs mixed equipment, you need one shop that can handle all of it.
Diagnostic-First Approach
We diagnose before we rebuild. Many symptoms attributed to "transmission failure" actually originate from the clutch, driveline, engine electronics, or shift controls. Our systematic diagnostic process identifies the true root cause before we quote expensive internal transmission work.
30+ Years of Heavy-Duty Experience
CTR has been rebuilding and replacing commercial truck transmissions since 1995. Our technicians have hands-on experience with every generation of the major platforms — from legacy Fuller 13-speeds to the latest UltraShift Plus and I-Shift AMTs.
Minimizing Your Downtime
Transmission repairs are inherently time-intensive, which is why we focus on fast, accurate diagnosis and efficient parts sourcing. We maintain supplier relationships that get components to our shop quickly, and our workflow gets your truck back to work as fast as possible.
All Makes, All Models, One Shop
Our technicians are fluent in every major commercial truck transmission platform on the road. From legacy manuals to the latest AMTs, we have the tools and expertise to get it done right.
Eaton Fuller — Manual
Eaton Fuller transmissions are the most widely used manual transmissions in the North American Class 8 truck market. We service the complete Eaton lineup:
- Fuller 9-speed (RT-6609, RT-8609)
- Fuller 10-speed (RT-610, RTLO-610)
- Fuller 13-speed (RT-6613, RTLO-16713)
- Fuller 15-speed (RTLO-16915)
Eaton Fuller — Automated Manual (AMT)
Fuller AMTs use the same basic gear train as manual Fullers but add an automated clutch actuator and electronic shift control system:
- Fuller AutoShift
- Fuller UltraShift
- Fuller UltraShift Plus
- Same gear train as manual Fullers with automated clutch actuator and electronic shift control
Allison Automatic Transmissions
Allison automatics are the standard in vocational applications — refuse trucks, dump trucks, transit buses, delivery trucks, fire apparatus, and concrete mixers.
- Torque converter diagnosis and replacement
- Internal clutch pack service and replacement
- Valve body diagnosis and rebuilding
- Output retarder service
Volvo I-Shift & Mack mDRIVE
The Volvo I-Shift and Mack mDRIVE are the same automated manual transmission platform:
- 12-speed AMT — standard on Volvo VNL/VNR and Mack Anthem/Pinnacle trucks
- Clutch wear and replacement
- Shift actuator diagnosis and repair
- Gearbox oil leak repair
Detroit DT12 Transmission
The Detroit DT12 is Daimler's 12-speed automated manual transmission:
- 12-speed AMT — standard in Freightliner Cascadia and Western Star trucks
- Clutch system diagnosis and repair
- Shift tower actuator failures
- Internal bearing and gear wear
Meritor & ZF Transmissions
Found in many older and vocational trucks, plus specialty applications:
- Meritor manual transmissions (including legacy Rockwell and Spicer product lines)
- ZF transmissions for European-origin platforms and specialty applications
- Complete overhauls
- Bearing replacement
Our Diagnostic-First Approach
We don't guess. We diagnose. Misdiagnosing a transmission issue is a costly mistake. Our systematic process ensures we identify the true root cause before any wrenches are turned, saving you time and money.
Electronic Diagnostics
OEM-level scan tools (Eaton ServiceRanger, Allison DOC, Volvo PTT, Detroit DDDL) to retrieve fault codes, view live data, perform active tests, and identify electronic and control system issues
Road Test Evaluation
Reproduce reported symptoms under actual operating conditions — assessing shift quality, engagement timing, noise, vibration, and response characteristics
Fluid Analysis
Transmission fluid condition, contamination level, and metallic particle content reveal internal wear patterns before a teardown
External Component Inspection
Shift linkage, clutch adjustment, driveshaft condition, engine mounts, and crossmember mounts can all produce symptoms that mimic internal transmission failure
Internal Inspection
When diagnostics indicate internal damage — controlled disassembly and component measurement to determine the scope of repair needed
Is Your Transmission Trying to Tell You Something?
Don't ignore the warning signs. Addressing transmission issues early can be the difference between a minor repair and a catastrophic failure. Here’s what to look, listen, and feel for.
Shifting Issues
- Grinding or crunching when shifting gears: Worn synchronizers or clutch issues (manual)
- Difficulty getting into or out of specific gears: Shift linkage, synchronizer, or internal damage
- Transmission pops out of gear under load: Worn detent springs, shift forks, or internal wear
- Delayed or harsh shift engagement: Valve body, solenoid, or clutch pack issues (auto/AMT)
- "Check Trans" or fault warning light illuminated: Electronic fault requiring scan tool diagnosis
Noises & Vibrations
- Whining, humming, or growling that changes with speed/gear: Bearing or gear wear
- Clicking or rattling in neutral: Input shaft bearing or countershaft bearing issues
- Clunking during gear engagement: Synchronizer, clutch, or U-joint issues
Leaks & Lights
- Transmission fluid leaks under the truck: Seal, gasket, or housing damage
- Burnt smell from the transmission area: Overheated fluid or clutch material
- Visible damage to clutch linkage or shift lever: External component failure
- Limp mode activation — restricted to limited gears: TCM-detected fault protecting against further damage
Serving the Greater Charlotte Area
Our shop in Concord, NC is conveniently located to serve fleets and owner-operators throughout the region.
Frequently Asked Questions
Keep Your Fleet Moving
Don't let transmission problems sideline your business. Contact our heavy-duty experts today for reliable diagnostics and repairs that get you back on the road fast.
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