Functional Test Procedure (Diagnostic Information and Procedures)

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Functional Test Procedure (2002-2003 Allison C/K Truck)

Step	Action	Yes	No
The Functional Test Procedure is the first step in diagnosing mechanical or hydraulic transmission conditions. The Functional Test provides procedures and references to the Symptom Diagnosis table for specific diagnostic information.
1	IMPORTANT: Engine performance can strongly affect transmission performance. Make sure that the complaint is not the result of poor engine performance before continuing. Verify the customer complaint.Has the customer complaint been verified?	Go to Step 2 .	-
2	IMPORTANT: Many transmissions have default actions that take place once a DTC fault is detected. These actions may appear to be transmission concerns. Has the Diagnostic System Check - Automatic Transmission been performed?	Go to Step 3 .	Go to Diagnostic System Check - Automatic Transmission .
3	Perform a visual inspection. Look for the following conditions: Vehicle damage. Transmission oil pan damage. Refer to Oil Pan Replacement . Transmission range selector cable damaged or out of adjustment. Refer to Automatic Transmission Range Selector Cable Adjustment or Automatic Transmission Range Selector Cable Replacement . Loose, worn, damaged or missing: Mounts or struts. Brackets. Mounting hardware. In one of these three cases, refer to Transmission Replacement (With 6.6L Engine) or Transmission Replacement (With 8.1L (L18) Engine) . Transmission cooler or cooler line restrictions. Refer to Automatic Transmission Oil Cooler Flushing and Flow Test . Fluid leaks. Refer to Fluid Leak Diagnosis . Was an item identified that needs service?	Go to the Appropriate Repair or Diagnosis Section.	Go to Step 4 .
4	Perform the Transmission Fluid Checking Procedure . Is the procedure complete?	Go to Step 5 .	Go to Transmission Fluid Checking Procedure .
5	Perform the Road Test Procedure . Did the vehicle exhibit any objectionable performance condition?	Go to Step 6 .	Go to Step 1 .
6	Did the vehicle exhibit objectionable torque converter operation?	Go to Step 15 .	Go to Step 7 .
7	Did the vehicle produce any objectionable noise condition?	Go to Symptoms - Automatic Transmission .	Go to Step 8 .
8	Did the vehicle exhibit a vibration condition?	Go to Step 9 .	Go to Step 10 .
9	Did the vibration occur only during TCC apply or release?	Go to Step 15 .	Go to Symptoms - Automatic Transmission .
10	Did the vehicle exhibit a shift speed condition such as low or high shift speeds?	Go to Symptoms - Automatic Transmission .	Go to Step 11 .
11	Check for unacceptable shift quality. Harsh, soft, delayed or no engagement Harsh, soft or delayed shifts Shift shudder, flare or tie-up Did the vehicle exhibit any of these shift quality conditions?	Go to Step 12 .	Go to Step 13 .
12	Perform the Line Pressure Check Procedure . Is the line pressure within specification?	Go to Symptoms - Automatic Transmission .	Go to Symptoms - Automatic Transmission .
13	Check for unacceptable shift pattern conditions? No upshift or downshift. Only one or two forward ranges. No FIRST range, no second-range, No third-range, no fourth-range or no fifth-range. Slipping. Non-first-range start. Did the vehicle exhibit any of these shift pattern conditions?	Go to Symptoms - Automatic Transmission .	Go to Step 14 .
14	Check for unacceptable range performance conditions? No PARK, no REVERSE or no DRIVE No engine braking. No gear selection. Incorrect gear selection. Did the vehicle exhibit any of these range performance conditions?	Go to Symptoms - Automatic Transmission .	System OK.
15	Check for these specific torque converter or TCC malfunctions? Stuck ON or OFF. Early or late engagement. Incorrect apply or release. Soft or harsh apply. Clunk or shudder. No torque multiplication. Excessive slip. Poor acceleration. Engine stalls. Did the vehicle exhibit any of these torque converter or TCC conditions?	Go to Torque Converter Diagnosis Procedure .	System OK.