GM Service Manual Online
For 1990-2009 cars only

Functional Test Procedure (1998 G Van 4L60-E)

Step

Action

Value(s)

Yes

No

1

Perform the Transmission Fluid Check .

Is the fluid level correct?

--

Go to Step 2

--

2

Check for VCM trouble codes, both current and history.

Are VCM trouble codes present?

--

Go to Diagnostic Trouble Code Identification

Go to Step 3

3

  1. Perform the Electrical/Garage Shift Procedure .
  2. Perform the Road Test .

Was the condition duplicated?

--

Go to Step 4

Go to Step 12

4

Is a harsh or soft shift condition present?

--

Go to Step 7

Go to Step 5

5

Is the vehicle's performance poor?

--

Go to Torque Converter Clutch (TCC) Diagnosis

Go to Step 6

6

Is the engagement into Drive or Reverse delayed or missing?

--

Go to Step 7

Go to Step 9

7

Perform the Line Pressure Check .

Is the line pressure correct?

--

Go to Step 8

Go to Symptom Diagnosis Tables

8

Inspect the transmission wire harness connectors and the transmission range switch.

Was the condition found and corrected?

--

System OK

Go to Symptom Diagnosis Tables

9

Is vibration or noise a concern?

--

Go to Flexplate/Torque Converter Vibration Test

Go to Step 10

10

Is the fluid leaking?

--

Go to Fluid Leak Diagnosis and Repair

Go to Step 11

11

Are other transmission conditions present?

--

Go to Symptom Diagnosis Tables

Go to Step 12

12

Was the condition corrected?

--

Exit Table

Go to Step 1