Harsh Shifting???

[BROTHERSINBROWNCC]

Several Weeks Ago I Had The Spark Plugs, Wires, Oil Change And Trans-service Completed On My 1997 Buick Regal Gs. Just Recently, I Noticed The Transmission Making Harsh Shifting. When The Shift Is Made, There Is A Slight Hesitation, Not Too Noticable, Then A Harsh Hit As It Engages. I Heard Someone Say Something About Maybe One Of The Trans-valves Sticking? Could This Be The Culpret? The Problem Seems To Surface As The Car Warms Up. Any Pointers Would Be Appreciated.



A.g. - Il

[BNaylor]

Originally Posted by BROTHERSINBROWNCC

Several Weeks Ago I Had The Spark Plugs, Wires, Oil Change And Trans-service Completed On My 1997 Buick Regal Gs. Just Recently, I Noticed The Transmission Making Harsh Shifting. When The Shift Is Made, There Is A Slight Hesitation, Not Too Noticable, Then A Harsh Hit As It Engages. I Heard Someone Say Something About Maybe One Of The Trans-valves Sticking? Could This Be The Culpret? The Problem Seems To Surface As The Car Warms Up. Any Pointers Would Be Appreciated.



A.g. - Il

Typically on the 4T65E HD tranny it indicates high line pressure for whatever reason. Could be the pressure control solenoid (PCS) but not all the time. Try getting the computer scanned for any manufacturer specific tranny related DTC error codes such as P18XX, etc.

In the interim, try some Lubegard additive. May help free up the sticking valve if the tranny is not a total basket case.

[ontheedge02]

In response to the people with Buicks that are having the "harsh shifting" problem. I was have this too, when the car was warmed up and after I had changed the transmission fluid (which many others have experienced).

Finally, the problem has been solved. When re-filling the trans after draining all the fluid, I added 5 quarts and drove the car a short distace, then checked it and added another 1+ quart to get it to the proper level, following the instructions "not to over-fill".

I drove the car like this for several months, and as the weather started to warm up, the harsh shifting problem became worse, so I took it in to have it looked at. What they found is that there was a code P1811(trans takes more than .65 seconds to shift) stored causing the harsh shifting. They dropped the pan and found nothing. I had them flush the trans (and add lubeguard - red bottle with silver label) while they were at it. Since getting the car back, I have driven it several hunderd miles with no signs of the problem.

What they think happened is that when I drove it low on fluid, I sucked in an air bubble causing the trans code to be set. All I think I really needed to do is clear the code, and I think I would have been fine.

This was a tough lessen (but it could have been worse). I think others might have the same problem as this seems to surface after the fluid has been changed.

Good Luck!

[paulfischer]

i believe that after a fluid and filter change it takes 7.4 qrts.

[BNaylor]

Originally Posted by paulfischer

i believe that after a fluid and filter change it takes 7.4 qrts.

I agree with your figure having going through 2 filter changes and ATF replenishment on my '99 Regal LS (100K miles).

[BNaylor]

Originally Posted by ontheedge02

In response to the people with Buicks that are having the "harsh shifting" problem. I was have this too, when the car was warmed up and after I had changed the transmission fluid (which many others have experienced).

Finally, the problem has been solved. When re-filling the trans after draining all the fluid, I added 5 quarts and drove the car a short distace, then checked it and added another 1+ quart to get it to the proper level, following the instructions "not to over-fill".

I drove the car like this for several months, and as the weather started to warm up, the harsh shifting problem became worse, so I took it in to have it looked at. What they found is that there was a code P1811(trans takes more than .65 seconds to shift) stored causing the harsh shifting. They dropped the pan and found nothing. I had them flush the trans (and add lubeguard - red bottle with silver label) while they were at it. Since getting the car back, I have driven it several hunderd miles with no signs of the problem.

What they think happened is that when I drove it low on fluid, I sucked in an air bubble causing the trans code to be set. All I think I really needed to do is clear the code, and I think I would have been fine.

This was a tough lessen (but it could have been worse). I think others might have the same problem as this seems to surface after the fluid has been changed.

Good Luck!

Thanks for sharing your story with us. It has plagued and continues to bug many GM "W" body owners and other similar platforms. Some have spent up to $3K to either resolve the problem or finding that the problem comes back to haunt them.

On my '99 Regal LS this is my story to share. Had the filter and ATF changed around 50K and no problems until 97K miles when the tranny started to whine and upshift harshly. Checked for tranny specific DTC error codes (P18XX) and found none. Most of the time it would run fine after turning the ignition off for a while and re-starting.

Got Lubegard instant flush and ran it through per the instructions. Then dropped the pan, drained and did a visual inspection. Found nothing significant or no metal shavings. Let it drip drain overnight. Changed the filter with a genuine AC Delco (TF304), put a new gasket on, torqued pan, and re-plenshed with approximately 7.0 quarts of Castrol Dextron-III. I added the Lubegard protectant with LXE (10 oz).

Just for general principle had the ECU reset (adaptive shift points) and ran the car and found out that the symptoms greatly improved as it re-learned. The whine was cut down significantly and the harsh upshifts were reduced. It started improving over the next 500 miles. Then I added another another 10 oz. of the Lubegard and have put over 2K miles on and all problems disappeared (no whine or harsh upshifts). I really don't know if this is a permanent fix but the Lubegard seems to work at least in my scenario.