Symptom Diagnosis. GMC Truck GMC K Sierra

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2000 🢒 GMC K Sierra - 4WD 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L80-E 🢒 Symptom Diagnosis

Diagnostic Category

Diagnostic Information

The following table consists of eight diagnostic categories that are located in the left-hand column. Using this column, choose the appropriate category based on the operating conditions of the vehicle or transmission. After selecting a category, use the right-hand column to locate the specific symptom diagnostic information.

Fluid Diagnosis

This category contains the following topics:

•	Fluid condition (appearance, contaminants, smell, overheating)

•	Line pressure (high or low)

•	Fluid leaks

•	Refer to Transmission Fluid Check .

•	Refer to Fluid Foaming .

•	Refer to Transmission Overheats .

•	Refer to Transmission Overheats at WOT .

•	Refer to High Line Pressure .

•	Refer to Low Line Pressure .

•	Refer to Inadequate Lubrication at Low Line or Heavy Loads .

•	Refer to Inadequate Lubrication .

•	Refer to Fluid Leak Diagnosis .

•	Refer to Case Extension Bearing/Seal Failed .

•	Refer to Oil Out the Vent Tube .

•	Refer to Automatic Transmission Fluid Leaks .

Noise and Vibration Diagnosis

This category contains the following topics:

•	Noise (drive gear, final drive, whine, growl, rattle, buzz, popping)

•

Vibration

•	Refer to Noise .

•	Refer to Vibration .

•	Refer to Flexplate/Torque Converter Vibration Test .

Range Performance Diagnosis

This category contains the following topics:

•	Drives in Neutral

•	No Park/Neutral

•	No Reverse

•	Engine stalling

•

No Drive

•	No engine braking

•	No or incorrect gear selection

•	Refer to Forward Motion in Neutral .

•	Refer to No Park .

•	Refer to No Reverse .

•	Refer to Engine Stall .

•	Refer to No Torque in Reverse and Third .

•	Refer to Loss of Power .

•	Refer to No Torque in Second Gear .

•	Refer to Loss of Drive .

•	Refer to No Overrun Braking - D1 .

•	Refer to No Engine Braking - D1 .

•	Refer to No Overrun Braking - D2 .

•	Refer to No Engine Braking - D2 .

•	Refer to No Second Gear Engine Braking - D2 .

•	Refer to No Overrun Braking - D3 .

•	Refer to No Engine Braking - D3 .

•	Refer to Engine Starts in Gear .

•	Refer to Shift Lever Indicates Wrong Gear .

•	Refer to No Gear Selection .

•	Refer to Remains in Park .

•	Refer to Difficult to Shift Out of Park .

•	Refer to Does Not Stay in Park .

Shift Quality (Feel) Diagnosis

This category contains the following topics:

•	Erratic shifts

•	Harsh, soft, delayed or slipping shifts

•	Harsh, soft, or delayed engagement

•	Refer to Erratic Shift Quality .

•	Refer to Harsh Shifts .

•	Refer to Transmission Slips .

•	Refer to Harsh Shift 3 to 4 .

•	Refer to Harsh Shift 4 to 3 .

•	Refer to Harsh Shift D4 to D3, D2, or D1 .

•	Refer to Soft Shifts .

•	Refer to Delayed Shift 1 to 2 .

•	Refer to Soft Shift 2 to 3 .

•	Refer to Soft Shift D3 to D2 .

•	Refer to Soft Shift 3 to 2 .

•	Refer to No D3 to D2 .

•	Refer to No D2 to D1 .

•	Refer to Harsh Shift D to R .

•	Refer to Soft Shift into R .

•	Refer to Soft Shift R to D .

Shift Pattern

This category contains the following topics:

•	One forward gear missing or slipping

•	One forward gear only

•	Two forward gears only

•	Non-First gear start

•	Refer to No First Gear - D1 .

•	Refer to No First Gear - D2 .

•	Refer to No First Gear - D4 .

•	Refer to No Second Gear - D1 .

•	Refer to No Second Gear - D2 .

•	Refer to No Second Gear - D4 .

•	Refer to No Second Gear - D3 .

•	Refer to No Third Gear - D3 .

•	Refer to No Third Gear - D4 .

•	Refer to No Fourth Gear - D4 .

•	Refer to First Gear Only - D4 .

•	Refer to Second Gear Only - D4 .

•	Refer to First and Second Gear Only - D4 .

•	Refer to First and Fourth Gear Only - D4 .

•	Refer to Second and Third Gear Only - D4 .

•	Refer to Third and Fourth Gear Only - D4 .

•	Refer to Second Gear Starts .

•	Refer to Third Gear Starts .

•	Refer to Fourth Gear Starts .

Shift Speed Diagnosis

This category contains the following topic:

Inaccurate or inconsistent shift points

Refer to Inaccurate Shift Points .

Torque Converter Diagnosis

This category contains the following topics:

•	Torque Converter Diagnosis

•	TCC does not apply

•	TCC does not release

•	TCC apply/release quality

•	Poor acceleration/No torque multiplication

•	Converter Ballooning

•	Engine Stall

•	Refer to Torque Converter Diagnosis .

•	Refer to Flexplate/Torque Converter Vibration Test .

•	Refer to No Torque Converter Clutch Apply .

•	Refer to Torque Converter Clutch Stuck On .

•	Refer to Soft Torque Converter Clutch Apply .

•	Refer to Incorrect Torque Converter Clutch Apply or Release .

•	Refer to No Torque Multiplication .

•	Refer to Torque Converter Clutch Slipping .

•	Refer to Converter Ballooning .

•	Refer to Engine Stall in Neutral .

Symptom not found or no symptom detected

•	Refer to Transmission Fluid Check .

•	Refer to Road Test .

•	Refer to Line Pressure Check .