The 2021 Chrysler 300 is a solid rear-wheel-drive sedan, but the ZF 8-speed transmission and Hemi engines bring specific issues. These are late-production LX cars, so many early bugs are sorted, but transmission coolers and lifter failures remain real concerns.
ZF 8-Speed Transmission Oil Cooler Failure
Common · high severityTypical onset: 50,000-90,000 mi
Symptoms: Transmission fluid in coolant or coolant in transmission, Milky pink fluid on dipstick or in overflow bottle, Harsh shifting or loss of gears after contamination, Check engine light with transmission temp codes
Fix: Replace internal transmission oil cooler and flush both cooling system and transmission. If contamination went unnoticed, transmission rebuild may be required. 6-8 hours labor for cooler replacement alone, 18-25 hours if transmission needs rebuild.
Estimated cost: $1,200-2,000 (cooler only), $4,500-7,000 (if transmission damaged)
5.7L Hemi Lifter and Camshaft Failure
Occasional · high severityTypical onset: 60,000-120,000 mi
Symptoms: Cold-start tick or rattle that persists beyond 30 seconds, MDS (cylinder deactivation) system codes, Loss of power or rough idle, Metal shavings in oil on analysis
Fix: Requires both camshaft replacement and all 16 lifters, often with rocker arms. Heads come off for proper inspection. 16-20 hours labor for cam and lifter job. Some techs recommend full MDS delete kits to prevent repeat failure.
Estimated cost: $4,000-6,500
6.4L SRT Engine Bearing and Short Block Failures
Rare · high severityTypical onset: 40,000-80,000 mi
Symptoms: Knocking or ticking from lower engine, Low oil pressure warnings, Catastrophic failure with metal debris in oil pan, Often happens suddenly with no warning
Fix: Main or rod bearing failure requires short block or complete engine replacement. Some failures traced to oil pump issues or debris from manufacturing. 24-30 hours labor for engine R&R and short block swap.
Estimated cost: $8,000-14,000
Transmission Output Shaft Bearing Whine
Occasional · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Whining or humming noise that changes with vehicle speed, not engine RPM, Noise present in all gears, neutral, or coasting, No loss of function initially, but can lead to seal leaks
Fix: Requires transmission removal and disassembly to replace output shaft bearing and seal. 8-10 hours labor. Often discovered during routine fluid service when noise becomes undeniable.
Estimated cost: $1,800-2,800
Fuel Filter Restriction (V8 Models)
Occasional · medium severityTypical onset: 80,000-130,000 mi
Symptoms: Hesitation or stumbling under hard acceleration, Longer cranking time when starting, Fuel pump codes or low fuel pressure readings, Reduced power at highway speeds
Fix: In-tank fuel filter/strainer clogs from sediment. Requires fuel tank drop and pump module replacement or cleaning. 3-4 hours labor. Not a serviceable filter—full pump module typically replaced.
Estimated cost: $600-1,100
Windshield Stress Cracks and Seal Leaks
Occasional · low severitySymptoms: Spontaneous cracks from lower windshield corners, Water leaks at A-pillar during car washes or rain, Wind noise at highway speeds, NHTSA recall addressed some batches with defective glass
Fix: Windshield replacement with proper urethane cure time. Recall covers some VINs; check with dealer. 2-3 hours labor if not covered under recall or insurance.
Estimated cost: $400-800 (out of pocket)
The 3.6L V6 is the safest bet for reliability; 5.7L Hemi is solid if maintained religiously, but avoid 6.4L SRT models unless you have deep pockets for potential engine work.
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.