Power window thump

[chadc77]

I have a '04 GMC 1500 and when I let my window down there is a CLUNK! The passenger side does not do this. Is there away to adjust the regulator and window slide?

[biochemist]

I have a '04 GMC 1500 and when I let my window down there is a CLUNK! The passenger side does not do this. Is there away to adjust the regulator and window slide?

 

<{POST_SNAPBACK}>

 

 

Both windows on mine make a thud if you roll them all the way down, I have heard it on other trucks too, so I never thought much about it . Not sure what you mean by clunk, mine sounds more like a thud, but I have no issues with that, they work fine. Did you get the transmission issue resolved ? Let me know, later,

[chadc77]

Thanks for the info, I just wasnt sure if this was a concern or not. NO the trans is not fixed yet, GM put a new tranny and PCM in the truck. There is suposed to be a engineer coming in a few weeks to look @ the issue............

[USA1Fan]

Definitely normal. My '04 Silverado does it too.

[biochemist]

Thanks for the info, I just wasnt sure if this was a concern or not. NO the trans is not fixed yet, GM put a new tranny and PCM in the truck.  There is suposed to be a engineer coming in a few weeks to look @ the issue............

 

<{POST_SNAPBACK}>

 

 

Huh, odd...so after they put the new transmission in it still does not shift right? I guess I was never clear on the condition to begin with...do you feel the 1-2 upshift should be unnoticable? Mine shifts really smooth most of the time, sometimes I cannot even tell it shifts 1-2, but occasionally it will shift a little firmer, you can feel it anyway, but I was told that is normal. Totally depends on throttle pressure and speed too...I guess the transmission is trying to continuously learn how you drive...No codes set or lights or anything, so I think it is normal. It also does this more in cold weather, which again is a normal characteristic. Maybe GM-Tech could help everyone out by explaining a bit more about adaptive shifting and cold weather shifting? Anyway, let us know, later,

[GM-Tech]

You know, I could try to explain the process in my own words, but GM does a much better job at it that I think that's the way to go here. Here's how it works...

 

--------------------------

 

The 4L60-E transmission utilizes a line pressure control system during upshifts to compensate for the normal wear of transmission components. By adjusting the line pressure, the PCM can maintain acceptable transmission shift times. This process is known as "adaptive learning" or "shift adapts" and is similar to the closed loop fuel control system used for the engine.

 

In order for the PCM to perform a "shift adapt," it must first identify if an upshift is acceptable to analyze. For example, upshifts that occur during cycling of the A/C compressor or under extreme throttle changes could cause the PCM to incorrectly adjust line pressure. When an upshift is initiated, a number of contingencies, such as throttle position, transmission temperature, and vehicle speed, are checked in order to determine if the actual shift time is valid to compare to a calibrated desired shift time. If all the contingencies are met during the entire shift, then the shift is considered valid and the adapt function may be utilized if necessary.

 

Once an adaptable shift is identified, the PCM compares the actual shift time to the desired shift time and calculates the difference between them. This difference is known as the shift error. The actual shift time is determined from the time that the PCM commands the shift to the start of the engine RPM drop initiated by the shift. If the actual shift time is longer than the calibrated desired shift time, a soft feel or slow engagement, then the PCM decreases current to the pressure control (PC) solenoid in order to increase line pressure for the next, same, upshift under identical conditions. If the actual shift time is shorter than the calibrated desired shift time, a firm engagement, then the PCM increases current to the PC solenoid in order to decrease line pressure for the next, same, upshift under identical conditions.

 

The purpose of the adapt function is to automatically compensate the shift quality for the various vehicle shift control systems. It is a continuous process that will help to maintain optimal shift quality throughout the life of the vehicle.

 

Clearing Transmission Adaptive Pressure (TAP)

 

Transmission adaptive pressure (TAP) information is displayed and may be reset using a scan tool.

 

The adapt function is a feature of the PCM that either adds or subtracts line pressure from a calibrated base line pressure in order to compensate for normal transmission wear. The TAP information is divided into 13 units, called cells. The cells are numbered 4 through 16. Each cell represents a given torque range. TAP cell 4 is the lowest adaptable torque range and TAP cell 16 is the highest adaptable torque range. It is normal for TAP cell values to display zero or negative numbers. This indicates that the PCM has adjusted line pressure at or below the calibrated base line pressure.

 

Updating TAP information is a learning function of the PCM designed to maintain acceptable shift times. It is not recommended that TAP information be reset unless one of the following repairs has been made:

 

• Transmission overhaul or replacement

 

• Repair or replacement of an apply or release component, clutch, band, piston, servo

 

• Repair or replacement of a component or assembly which directly affects line pressure

 

Resetting the TAP values using a scan tool will erase all learned values in all cells. As a result, the PCM will need to relearn TAP values. Transmission performance may be affected as new TAPs are learned. Learning can only take place when the PCM has determined that an acceptable shift has occurred. The PCM must also relearn TAP values if it is replaced.

[jeffbf89]

Wow! I will never ever need that information but I love knowing how stuff works and that is pretty cool.

[biochemist]

You know, I could try to explain the process in my own words, but GM does a much better job at it that I think that's the way to go here.  Here's how it works...

 

--------------------------

 

The 4L60-E transmission utilizes a line pressure control system during upshifts to compensate for the normal wear of transmission components. By adjusting the line pressure, the PCM can maintain acceptable transmission shift times. This process is known as "adaptive learning" or "shift adapts" and is similar to the closed loop fuel control system used for the engine.

 

In order for the PCM to perform a "shift adapt," it must first identify if an upshift is acceptable to analyze. For example, upshifts that occur during cycling of the A/C compressor or under extreme throttle changes could cause the PCM to incorrectly adjust line pressure. When an upshift is initiated, a number of contingencies, such as throttle position, transmission temperature, and vehicle speed, are checked in order to determine if the actual shift time is valid to compare to a calibrated desired shift time. If all the contingencies are met during the entire shift, then the shift is considered valid and the adapt function may be utilized if necessary.

 

Once an adaptable shift is identified, the PCM compares the actual shift time to the desired shift time and calculates the difference between them. This difference is known as the shift error. The actual shift time is determined from the time that the PCM commands the shift to the start of the engine RPM drop initiated by the shift. If the actual shift time is longer than the calibrated desired shift time, a soft feel or slow engagement, then the PCM decreases current to the pressure control (PC) solenoid in order to increase line pressure for the next, same, upshift under identical conditions. If the actual shift time is shorter than the calibrated desired shift time, a firm engagement, then the PCM increases current to the PC solenoid in order to decrease line pressure for the next, same, upshift under identical conditions.

 

The purpose of the adapt function is to automatically compensate the shift quality for the various vehicle shift control systems. It is a continuous process that will help to maintain optimal shift quality throughout the life of the vehicle.

 

Clearing Transmission Adaptive Pressure (TAP)

 

Transmission adaptive pressure (TAP) information is displayed and may be reset using a scan tool.

 

The adapt function is a feature of the PCM that either adds or subtracts line pressure from a calibrated base line pressure in order to compensate for normal transmission wear. The TAP information is divided into 13 units, called cells. The cells are numbered 4 through 16. Each cell represents a given torque range. TAP cell 4 is the lowest adaptable torque range and TAP cell 16 is the highest adaptable torque range. It is normal for TAP cell values to display zero or negative numbers. This indicates that the PCM has adjusted line pressure at or below the calibrated base line pressure.

 

Updating TAP information is a learning function of the PCM designed to maintain acceptable shift times. It is not recommended that TAP information be reset unless one of the following repairs has been made:

 

  •  Transmission overhaul or replacement 

 

  •  Repair or replacement of an apply or release component, clutch, band, piston, servo 

 

  •  Repair or replacement of a component or assembly which directly affects line pressure 

 

Resetting the TAP values using a scan tool will erase all learned values in all cells. As a result, the PCM will need to relearn TAP values. Transmission performance may be affected as new TAPs are learned. Learning can only take place when the PCM has determined that an acceptable shift has occurred. The PCM must also relearn TAP values if it is replaced.

 

<{POST_SNAPBACK}>

 

 

Whoa That is some good info...so, basically it is always comparing and learing past or recent shifts and shift patterns, and the corresponding inputs you mention, for the adjustment of current or future shift points for optimization ...trying to provide the best shifts possible...complicated, but cool Thanks for the info, later,

[biochemist]

So, under identical conditions (in the GM info above)...it would be difficult to replicate an exact set of driving conditions...so I assume it just stores sets of criteria and when that condition set is seen again by the system, it corrects whatever needs to be corrected from the last shift. Is this right or does identical actually mean a small range of a certain conditions? I would also guess there are only so many sets it can store even though there are almost an infinite set of ways to drive...throttle pressure, incline, fluid temperature...etc. I am just trying to figure out what leads to different feeling shifts from, 1-2 upshifts for instance, since that shift has been talked about quite a bit recently, why are some completely unnoticable while others upshifts you feel, not much, but you do know the transmission shifted...Just trying to learn about the system, pretty cool and seems to work very well...later,