The 2007 G55 AMG is powered by the supercharged M113K V8 making 469 hp, mated to a 5-speed automatic. It's essentially a military-grade truck with AMG performance bolted on—incredibly capable but plagued by heat-related transmission failures and eventually catastrophic engine bearing issues if not meticulously maintained.
Transmission Valve Body & Conductor Plate Failure (722.6 5-Speed)
Common · high severity
Typical onset: 70,000-110,000 mi
Symptoms: Harsh or delayed shifts, especially 2-3 or 3-4, Limp mode with transmission fault codes, Slipping between gears under load, Transmission overheating warnings
Fix: Replace valve body and 13-pin conductor plate; often the transmission cooler and cooler lines fail simultaneously causing ATF overheating. Full external cooler upgrade recommended. 8-12 hours labor for transmission service.
Estimated cost: $2,800-4,500
M113K Supercharged Engine Bearing Failure
Occasional · high severity
Typical onset: 100,000-150,000 mi
Symptoms: Metallic knocking or ticking from lower engine, worsens with RPM, Low oil pressure warnings especially at idle when hot, Metal shavings or glitter in oil during changes, Sudden catastrophic engine failure if ignored
Fix: Requires full engine teardown; rod bearings and main bearings wear prematurely, especially if oil changes were extended or wrong oil used. Many shops recommend short block replacement over rebuild due to crankshaft journal wear. 40-60 hours labor.
Estimated cost: $12,000-18,000
Supercharger Nose Bearing & Coupler Failure
Occasional · medium severity
Typical onset: 80,000-130,000 mi
Symptoms: Whining or grinding noise from front of engine that increases with RPM, Reduced boost pressure and power loss, Rubber coupler debris in intake tract, Supercharger oil contamination visible on inspection
Fix: Supercharger must be removed and rebuilt—nose bearing and rubber isolator coupler wear out. DIY rebuild kits available but requires special tools. 6-10 hours labor for R&R and rebuild.
Estimated cost: $1,800-3,200
Air Suspension Compressor & Strut Leaks
Common · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Vehicle sags overnight or after sitting, especially rear, Compressor runs constantly or excessively, Warning lights for suspension malfunction, Uneven ride height side-to-side
Fix: Airmatic struts develop leaks in bellows; compressor overworks and fails. Each corner needs replacement when leaking; compressor is separate. 2-3 hours per strut, 4-5 hours for compressor.
Estimated cost: $1,200-2,000 per strut; $1,800-2,500 for compressor
Transfer Case Chain Stretch & Output Seal Leaks
Occasional · medium severity
Typical onset: 90,000-140,000 mi
Symptoms: Clunking or rattling during acceleration or deceleration, Gear oil leaking from front or rear output seals, Grinding noise when engaging 4WD, Difficulty shifting into low range
Fix: Transfer case chain stretches over time from the torque; output seals fail from age. Chain replacement requires case disassembly; seals alone are 3-4 hours, full chain service is 8-12 hours.
Estimated cost: $800-1,500 for seals; $2,500-4,000 for chain
Engine & Transmission Mounts
Common · low severity
Typical onset: 60,000-90,000 mi
Symptoms: Excessive vibration at idle, especially in Drive, Clunking when shifting from Park to Drive or Reverse, Visible engine movement when revving in Park, Transmission tunnel heat and vibration
Fix: M113K torque destroys mounts quickly; six total mounts (engine and transmission). Must use OE or high-quality aftermarket; cheap mounts fail in under 20k. 4-6 hours for all mounts.
Estimated cost: $1,200-2,000
Owner tips
Use only MB 229.5 spec oil and change every 5,000 miles maximum—the M113K supercharged engine is notoriously sensitive to oil quality and heat
Upgrade transmission cooler and install auxiliary trans temp gauge; 722.6 runs hot and longevity depends on staying under 200°F
Inspect supercharger oil level every oil change through the fill plug—low oil kills the nose bearing quickly
Keep detailed records—these are $150k+ trucks when new, and deferred maintenance becomes catastrophically expensive
Only buy if you have comprehensive service records showing religious 5k oil changes and proactive transmission maintenance—these are money pits without documentation, but legendary trucks when properly maintained.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: AGM battery required; located under passenger seat or in rear cargo area
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Every control module on the 2002-2007 Mercedes-Benz G55 AMG — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
📍 Under driver and passenger seats, mounted to seat frame
🔧 Star Diagnosis or Autel MaxiSys
⚠️ Controls power seat adjustment and memory. Two modules (driver/passenger) if both seats powered.
Fuel Pump Control Module (FPCM)0.5 hr R&Rno coding
📍 Rear cargo area, integrated with SAM-R or separate near fuel tank
⚠️ May be integrated into SAM-R on some production dates; controls fuel pump relay and pressure.
Bi-Xenon Control Unit (XCU)0.5 hr R&Rrelearn only +0.2 hr▸ programming details
📍 Behind each headlight assembly in engine bay
🔧 Star Diagnosis or Autel MaxiSys
⚠️ Two modules (left/right); controls HID ballast and auto-leveling. Only on Xenon-equipped vehicles.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2007 Mercedes-Benz G55 AMG 5.4L Supercharged V8 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.