P1870: Transmission Component Slipping
4 vehicles · 3 makes · $1,500-$3,800 repair
Most Reported On
P1870 is an OBD-II diagnostic trouble code meaning “Transmission Component Slipping.” This manufacturer-specific code (common on GM and Ford automatics, e.g. 4L60E) means the computer detected slippage between transmission components, most often at the torque converter clutch, where commanded engagement does not match actual behavior. When it sets, the PCM typically raises line pressure to protect the transmission and may lock out the converter clutch. Symptoms include harsh or delayed shifts, RPM flare/slipping, and reduced fuel economy. It often points to a worn valve body bore or TCC components and should be addressed before further internal damage occurs. This code is most commonly reported on 2000-2007 GMC Sierra 1500, 2002-2013 Chevrolet Avalanche, and 2001-2008 Pontiac Grand Prix, plus 1 other vehicle, with repair costs ranging from $1,500 to $3,800.
Common Causes
Typical Repair Cost
Based on 4 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P1870, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
Vehicles Affected (4)
FAQ
What does P1870 mean?
P1870 stands for "Transmission Component Slipping." This manufacturer-specific code (common on GM and Ford automatics, e.g. 4L60E) means the computer detected slippage between transmission components, most often at the torque converter clutch, where commanded engagement does not match actual behavior. When it sets, the PCM typically raises line pressure to protect the transmission and may lock out the converter clutch. Symptoms include harsh or delayed shifts, RPM flare/slipping, and reduced fuel economy. It often points to a worn valve body bore or TCC components and should be addressed before further internal damage occurs.
What are the most common causes of P1870?
The most common causes of P1870 are: Worn torque converter clutch (TCC) regulator valve bore in the valve body, Faulty TCC solenoid or PWM solenoid, Worn or failing torque converter clutch, Low or degraded transmission fluid, Worn internal clutches or seals (e.g., input shaft O-ring), Worn valve body / internal hydraulic leak. The specific cause varies by vehicle.
How much does it cost to fix P1870?
Repair costs for P1870 range from $1,500 to $3,800, depending on the vehicle and root cause.
Which vehicles are affected by P1870?
Au7o has documented P1870 across 4 vehicle models from 3 manufacturers: Chevrolet, GMC, Pontiac.
Sources (12)
- mediaBNB Gears: 4L60E Transmission Failure Points: Symptoms, Fixes
- mediaCherish Your Car: 4L60E Transmission Problems: What Fails, What Survives
- ForumGMT400: 4L60E trouble shooting guide STICKY
- ForumPirate 4x4: 4l60e no reverse
- mediaMonster Transmission: 4L60E No Reverse Causes, Symptoms, and Solutions
- articleChevy Avalanche Transmission Problems & Cost (4L60E/4L80E/6L80)
- Forum4L60E Question - Suddenly Lost 3/4 Gears
- ForumTransmission lost 3rd and 4th gears within 10 seconds | Chevy Avalanche Fan Club
- articleRebuild Tips for 4L60/E 3-4 Clutch Burnup | Sonnax
- articleTransmission Pressure Control Solenoid Failure May Cause Erratic Shifting - RepairPal
- Forum4T65E Hard Shift - Solution - Grand Prix Forums
- article2005 Pontiac Grand Prix Automatic Transmission Problems: 18 Complaints - CarComplaints
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.