IDENTIFICATION
Vehicle model is identified by 4th character (cars), or 5th character (trucks) of Vehicle Identification Number (VIN). VIN is stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION table.
The Hydra-Matic 4L60-E transmission can be identified by a letter code contained in identification number. Identification number is stamped on transmission case above oil pan rail on right rear side, or to rear of oil pan. (Scheme 592) Identification number contains information which must be used when ordering replacement parts. Transmission RPO code is M30.
| Body/Series (1) | Model |
|---|---|
| "C" | Sierra, Silverado, Suburban, Tahoe, Yukon & Yukon XL |
| "F" | Camaro & Firebird |
| "G" | Chevy Express & Savana |
| "K" | Sierra, Silverado, Suburban, Tahoe, Yukon, Yukon XL & AWD Escalade |
| "L" | AWD Astro & Safari |
| "M" | 2WD Astro & Safari |
| "S" | 2WD Blazer, Envoy, Jimmy, Sonoma & S10 Pickup |
| "T" | 4WD Blazer, Bravada, Envoy, Jimmy, Sonoma & S10 Pickup |
| "Y" | Corvette |
| (1) Vehicle body/series code is 4th character of VIN for cars or 5th character of VIN for trucks. | |
| (1) | Vehicle body/series code is 4th character of VIN for cars or 5th character of VIN for trucks. |
MODEL IDENTIFICATION
Scheme 592
DESCRIPTION & OPERATION
The Hydra-Matic 4L60-E is a fully automatic transmission consisting of a 3-element hydraulic torque converter with a Torque Converter Clutch (TCC). The 4-speed transmission is equipped with 2 planetary gear sets, 5 multiple-disc clutches, one sprag clutch, one roller clutch and a 2-4 band. (Scheme 593)
A hydraulic system, pressurized by a variable capacity vane type oil pump, provides pressure required to operate friction elements and automatic controls. The 4L60-E contains electronic solenoids that control hydraulic operations. A Powertrain Control Module (PCM) or Vehicle Control Module (VCM) receives input signals from Vehicle Speed Sensor (VSS), Throttle Position (TP) sensor and Transmission Fluid Pressure (TFP) manual valve position switch which incorporates the fluid temperature sensor. These input signals help the PCM/VCM determine when to switch 2 shift solenoids, 3-2 downshift solenoid, and/or TCC solenoid on or off. PCM/VCM can control line pressure through pressure control solenoid (force motor).
Line pressure control system compensates for normal wear of transmission components during upshifts in order to maintain optimal shift quality during life of transmission. PCM/VCM uses "adaptive learning" to maintain acceptable upshift times by adjusting line pressure. PCM/VCM compares actual "acceptable" shift time to calibrated desired shift time and calculates difference. An "acceptable" shift is considered valid if no inconsistent vehicle operations (A/C compressor cycling or extreme throttle changes) occurred during upshift. Line pressure is either increased or decreased depending on duration of upshift time.
