This is the master index to everything we've written about transmissions. Bookmark this page. Use it as your reference for any trans topic.
Identifying your transmission
Start here:
- How to Identify Your Transmission — by VIN, RPO, year, application
Then check specific guides:
Diagnosis
Warning signs:
- 10 Transmission Warning Signs — catch problems early
- Transmission Shudder vs Slip — tell the difference
- Transmission Noise Diagnosis — hum, whine, click decoded
Pan inspection:
- Transmission Pan Inspection — what the pan tells you
Pressure testing:
- Transmission Line Pressure Testing — gold-standard diagnosis
Codes:
- How to Read Transmission Codes — P-code guide
- 4L60E Common Failure Codes
- 4L80E Common Failure Codes
- 6L80 Common Failure Codes
Fluid:
- How to Check Transmission Fluid
- Burnt Transmission Fluid: What to Do
- How to Identify Transmission Fluid
- Transmission Fluid Types
- 6L80 Fluid Check Procedure
Failure modes
Clutch vs band vs hard part:
- Transmission Failure Modes — what failed and how to fix
Specific transmission rebuild guides
GM 4-speed:
GM 6-speed:
- Best 6L80 Rebuild Kit
- 6L80 Rebuild Cost
- 6L80 Mechatronics Rebuild
- 6L80 Wave Plate Replacement
- 6L80 Input Drum Failure
- 6L80 Thrust Washer Wear
- 6L80 P0775 Solenoid Codes
Ford:
Dodge/Cummins:
- Best 68RFE Rebuild Kit
- 68RFE Billet Input Shaft
- 68RFE Flexplate
- 68RFE Pressure Control Solenoid
- 68RFE Input Bushing
- 47RE/48RE Direct Clutch
Allison:
Classics:
Specific part guides
4L60E specific:
- 4L60E No Reverse / Sun Shell Fix
- 4L60E TCC Apply Piston
- 4L60E TCC Solenoid
- 4L60E Pump Rebuild
- 4L60E PR Valve Symptoms
- Sonnax PR Valve Install Guide
- 4L60E Reverse Input Drum
- 4L60E Governor Pressure Switch
- 4L60E TPS Effect on Shifts
- 4L60E Slipping Diagnosis
- 4L60E 3-4 Clutch Pack
4L80E specific:
- 4L80E PWM Solenoid
- 4L80E Shift Solenoid Replacement
- 4L80E Center Support
- 4L80E Pump Alignment
- 4L80E Direct Clutch HD Upgrade
- 4L80E Intermediate Band
- 4L80E Intermediate Sprag
- 4L80E Vacuum Modulator
Transmission comparisons
Direct comparisons:
- 4L60E vs 4L80E
- 4L80E vs 6L80
- 4L60E vs 6L80
- TH400 vs 4L80E
- 4R75W vs 4R70W
- 4L80E vs 6L90
- Allison 1000 vs 68RFE
- Allison vs 68RFE vs 6R140
Swap guides
Transmission swaps:
- LS Swap Transmission Guide
- 4L60E to 4L80E Swap
- TH400 to 4L80E Swap
- TH350 vs 700R4 Swap
- 4L60E to 4L65E Conversion
- 4L80E Swap Into Chevy
- Swap Planning Checklist
Cooling system
Heat management:
- Transmission Overheats in Traffic
- Transmission Cooler Installation
- Transmission Temperature Monitoring
- Diesel Cooler Sizing
- Transmission Cooler Line Leak
- Cooler Line Types
- Deep Transmission Pan
Service procedures
Maintenance:
- How to Flush Transmission Fluid
- Transmission Filter Guide
- Transmission Seal Kit Guide
- Transmission Bushing Kit
- Transmission Mount Failure
- Tow Rig Daily Maintenance
- Trans Ground Strap
- Trans Seal vs Gasket
Tow rig setup
HD applications:
- Diesel Tow Rig Setup
- 4L80E Direct Clutch HD
- Allison 1000 C2 HD
- 47RE/48RE Direct Clutch HD
- 4R70W Servo Upgrade
Performance upgrades
Shift kits and tuning:
Torque converters:
HD parts deep dives:
Rebuild process
Process guides:
- Transmission Rebuild Break-In
- 10 Transmission Rebuild Mistakes
- Transmission Rebuild Tool List
- Transmission Parts Buying Guide
Vehicle-specific applications
LS swap considerations:
Buying used trucks:
Misc valuable topics
Speed sensors:
Other repairs:
This is your starting point. Use this index to navigate to any transmission topic. New articles published regularly.
Looking for parts? Shop our complete catalog. Master rebuild kits, Sonnax HD upgrades, complete service supplies, all major transmissions. Free shipping over $70.
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