P1870: Transmission Component Slipping
10 vehicles · 4 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 1994-2010 Chevrolet Silverado 1500, 2000-2007 GMC Sierra 1500, and 2002-2013 Chevrolet Avalanche, plus 7 other vehicles, with repair costs ranging from $1,500 to $3,800.
Common Causes
Typical Repair Cost
Based on 11 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 (10)
4L60E Automatic Transmission 3-4 Clutch Pack and Sun Shell Failure (Slipping, Loss of 3rd/4th Gear)
4L60E Transmission 3-4 Clutch Failure / Slipping
4L60E Automatic Transmission 3-4 Clutch Failure (Loss of 3rd/4th Gear)
4L60E Transmission 3-4 Clutch Failure / Loss of 3rd & 4th
4L60E transmission loss of reverse (cracked sun shell / worn lo-reverse clutches)
4L60E automatic transmission 3-4 clutch pack and sun shell failure
4L60E Automatic Transmission 3-4 Clutch and Sunshell Failure
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 10 vehicle models from 4 manufacturers: Buick, Chevrolet, GMC, Pontiac.
Sources (12)
- ForumSOLVED! - Sudden loss of 3rd/4th gear (4L60E) - GMTNation
- ForumTransmission slipping in 3rd gear - SilveradoSierra.com
- articleMost Common 4L60E Transmission Problems & How to Fix Them - Motorverso
- 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
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.