TCC & Shift Road Test Procedure Astro / Safari (4L60E)

This video outlines the road test procedure for checking the quality of the "garage shifts," quality of the upshifts, and torque converter clutch lockup quality. The video goes over a few procedures that should be followed prior to the test and ends with a diagnosis. There is a detailed breakdown of the actual road test. As for the Pids, I could not find (MPH) and (Current Gear) to be included in the custom pids selection screen. Done on a 1997 GMC Safari.

[@freddaniali]

Great video. Your transmission may have a shift kit which makes the 1-2 shift a bit harsher.

[@BigZaddy2112]

Thank you for another outstanding video! I will perform this test….in regards to the checkballs, if they are out of place, is it obvious where they belong? Thanks!!!!

[@OldSchoolNoe]

I would say not obvious. This one has 12. You would need to get familiar with the 4L60E.

[@thesetruths1404]

Hi. I have a 1995 228,000 miles Sierra 1500 pickup. Only symptom I have is delayed shift from 1st to 2nd. It waits until 2,700 to 3,100 rpms. I can usually make it upshift to 2nd by easing up on fuel pedal just a little for a moment. Does it hot or cold, in cold weather and warm. Everything else works as it should. It will downshift from 2nd to 1st as it should. Fluid clean, good and exactly Full. Fuses all good. No CEL or codes stored. No visual leaks or consumption. Is this the 1-2 solenoid / solenoid A failing, more than likely? Or the 2-4 Servo? Or the 1-2 Accumulator valve? I have no CEL or stored codes. Also, is there a way to manually shift it to further narrow down issue? Thanks!

[@OldSchoolNoe]

Those items you listed would cause a rough shift, even some slipping if one/all went bad. Service information lists 5 possible causes (which I'm putting in order from most likely to less likely) 1. Pressure Switch Electrical Malfunction 2. Input Speed Sensor Electrical Malfunction 3. Incorrect Air gap/Electrical Malfunction of output speed sensor 4. Digital ratio adapter malfunction 5. PROM calibration incorrect