The 2007 Mazda B4000 is a rebadged Ford Ranger with the Cologne 4.0L SOHC V6 and 5R55E automatic transmission. This platform is known for catastrophic engine failures due to timing chain/cassette issues and transmission cooler line failures that can destroy the transmission.
Timing Chain Cassette Failure Leading to Engine Destruction
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: rattling noise on cold start that disappears after warmup, check engine light with cam/crank correlation codes, sudden catastrophic failure with metal shavings in oil, loss of power and misfires
Fix: The plastic timing chain cassettes disintegrate, causing slack that allows the chain to jump or break. Once broken, valves hit pistons requiring full engine rebuild or replacement. Preventive cassette replacement is 8-10 hours labor. After failure, expect 25-35 hours for short block or complete rebuild including machine work.
Estimated cost: $800-1,200 preventive cassette replacement; $4,500-7,500 for engine rebuild/replacement after failure
Transmission Oil Cooler Line Failure Causing Trans Destruction
Common · high severityTypical onset: 60,000-120,000 mi
Symptoms: pink milkshake appearance in coolant reservoir, transmission slipping or not shifting, overheating transmission, coolant loss without external leaks
Fix: The internal trans cooler in the radiator fails, allowing coolant and ATF to mix (the 'pink milkshake of death'). This contaminates the transmission requiring full flush, often followed by complete transmission failure within weeks. Once mixing occurs, expect trans cooler line replacement (3 hours), radiator (2 hours), full trans flush, and frequently transmission rebuild (12-15 hours) or replacement.
Estimated cost: $400-600 if caught immediately with lines/radiator only; $2,500-4,000 for transmission rebuild after contamination
Transmission Mount Failure
Common · medium severityTypical onset: 70,000-130,000 mi
Symptoms: clunking when shifting from park to drive or reverse, excessive vibration at idle, visible sagging of transmission tailshaft, harsh engagement into gear
Fix: The rear transmission mount deteriorates, allowing excessive drivetrain movement. Replacement requires supporting the transmission and is often done alongside other trans work. 1.5-2 hours labor for mount only.
Estimated cost: $200-350
Fuel Filter Clogging and Pump Strain
Occasional · medium severityTypical onset: 90,000-150,000 mi
Symptoms: hard starting especially when hot, loss of power under load, stalling or hesitation during acceleration, rough idle
Fix: The in-line fuel filter under the frame rail clogs, starving the engine and straining the in-tank pump. Many owners never change it per the 30k interval, leading to pump failure. Filter replacement is 0.5-1 hour. If pump fails, expect 2-3 hours for drop-tank replacement.
Estimated cost: $80-150 for filter; $500-800 for pump replacement
Lower Ball Joint and Control Arm Wear
Common · medium severityTypical onset: 80,000-140,000 mi
Symptoms: clunking over bumps, wandering steering, uneven tire wear on inside edges, play in front wheels when jacked up
Fix: The lower ball joints wear out and cannot be replaced separately on OEM arms—requires complete lower control arm assemblies. Both sides typically need replacement together. 3-4 hours labor for both sides including alignment.
Estimated cost: $600-900 for both sides
Rear Leaf Spring and Shackle Corrosion
Occasional · low severitySymptoms: sagging rear end, clunking from rear suspension, visible rust on spring hangers, uneven ride height side-to-side
Fix: In salt-belt states, the rear leaf spring shackles and hangers rust severely, sometimes breaking completely. Shackle bushings also deteriorate. Replacement of shackles and bushings is 2-3 hours; if hangers are rusted, expect welding work adding significant cost and time.
Estimated cost: $300-600 for shackles/bushings; $800-1,500 if frame welding required
Only buy if you can verify timing cassettes and trans cooler lines have been addressed—otherwise you're gambling with a $6,000 repair bill waiting to happen.
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.