Author Topic: '06 Buick Lucerne transmission issue  (Read 8567 times)

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7543
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
'06 Buick Lucerne transmission issue
« on: July 11, 2016, 02:41:48 PM »
The transmission in my wife's car feels like the torque converter is locking and unlocking trying to keep a steady speed with the cruise control especially but it also does it without using the cruise.  It has been doing it for a while but has been getting more noticeable lately.  Is this a problem easily taken care of or worse?  Thanks in advance.
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline LTZ C20

  • Senior Member
  • ****
  • Posts: 3795
  • "I'm here for a good time" -George Strait
Re: '06 Buick Lucerne transmission issue
« Reply #1 on: July 11, 2016, 03:13:58 PM »
Do you have access to a scan tool? One that can do live data streaming, if so, drive it while watching the torque converter clutch on/off data and confirm if that's actually what it is doing.
LTZ Cheyenne C20

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7543
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: '06 Buick Lucerne transmission issue
« Reply #2 on: July 11, 2016, 03:51:43 PM »
70 pages of stuff, I will look.  I've only needed to use it to check codes and stumbled across a screen that gives you the conditions when the code is set.  I guess I have some reading to do...  I don't have any light on at the moment and never had with this issue.  The tach jumps up a couple of hundred rpms and then drops back.
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline bd

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6438
Re: '06 Buick Lucerne transmission issue
« Reply #3 on: July 11, 2016, 06:11:35 PM »
Check the brake switch function and adjustment either directly or using your scan tool.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7543
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: '06 Buick Lucerne transmission issue
« Reply #4 on: July 11, 2016, 06:15:18 PM »
Check the brake switch function and adjustment either directly or using your scan tool.

if it was that wouldn't it kick off the cruise?
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline bd

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6438
Re: '06 Buick Lucerne transmission issue
« Reply #5 on: July 11, 2016, 06:54:34 PM »
Generally speaking, whether the TCC can be affected independently of cruise and brake lights depends on how the circuits are configured.  On our squares, a brake switch slightly out of adjustment can cause the TCC to cycle erratically w/o affecting cruise or brake lights.  The most common scenario is a switch bumped ever so slightly out of adjustment by inadvertently catching your toe under the brake pedal and lifting slightly.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7543
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: '06 Buick Lucerne transmission issue
« Reply #6 on: July 11, 2016, 07:01:45 PM »
Generally speaking, whether the TCC can be affected independently of cruise and brake lights depends on how the circuits are configured.  On our squares, a brake switch slightly out of adjustment can cause the TCC to cycle erratically w/o affecting cruise or brake lights.  The most common scenario is a switch bumped ever so slightly out of adjustment by inadvertently catching your toe under the brake pedal and lifting slightly.

I'll give it a try Friday when I get back up to where the car is.
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline Stewart G Griffin

  • Senior Member
  • ****
  • Posts: 3324
Re: '06 Buick Lucerne transmission issue
« Reply #7 on: July 11, 2016, 09:54:46 PM »
Another thing to experiment with is when these symptoms are going on, gently press the brake pedal----not enough to apply the brakes, but just enough to click the switch.   And see what happens.

Sorry can't get into more detail right now----getting sleepy.

Offline Irish_Alley

  • Tim
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13319
  • Family is not an important thing. It's everything.
Re: '06 Buick Lucerne transmission issue
« Reply #8 on: July 13, 2016, 09:09:06 AM »
those gm trans are controled by the ecm. your tps, brake switch, coolant temp, speed, MAF  and gear dictate if the ecm will lock up the T/C. inside of the trans you have the valve body,  faulty TCC,Bad o-rings, excess wear in TCC and a torque convertor soliniod that can cause the issue. sometimes cleaning the maf and resetting the computer via battery disconect can fix the problem or temperarly fix it. if memory serves me right its the 4t65 trans, the same trans we have in the impalas. some people never had one problem with them, others they turn into a nighmare.
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7543
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: '06 Buick Lucerne transmission issue
« Reply #9 on: July 13, 2016, 09:16:54 AM »
those gm trans are controled by the ecm. your tps, brake switch, coolant temp, speed, MAF  and gear dictate if the ecm will lock up the T/C. inside of the trans you have the valve body,  faulty TCC,Bad o-rings, excess wear in TCC and a torque convertor soliniod that can cause the issue. sometimes cleaning the maf and resetting the computer via battery disconect can fix the problem or temperarly fix it. if memory serves me right its the 4t65 trans, the same trans we have in the impalas. some people never had one problem with them, others they turn into a nighmare.

Mine has always done it and wasn't noticeable until lately.  Now it shudders a little when locking back it which tells me something is starting to get weak.  125K miles on it, have to expect things starting to go wrong with a 10+ year old car
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7543
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: '06 Buick Lucerne transmission issue
« Reply #10 on: July 13, 2016, 09:19:13 AM »
Do you have access to a scan tool? One that can do live data streaming, if so, drive it while watching the torque converter clutch on/off data and confirm if that's actually what it is doing.

Read the manual a couple of times and this one doesn't seem to be fancy enough for the live data streaming.  It doesn't do ABS or Airbag sensors either... :-(
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline Irish_Alley

  • Tim
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13319
  • Family is not an important thing. It's everything.
Re: '06 Buick Lucerne transmission issue
« Reply #11 on: July 13, 2016, 09:29:31 AM »
if its shuttering or aka TCC rpm oscillation, i dont think its getting weak. what its doing is either loosing fluid pressure or youre getting a crappy signal from the ecm. if something was getting weak i wouldnt think it would oscillate, i would think it would just slip. If the oring has a crack in it, It might allow it to build pressure then release it then build it back up. I would start with a disconnect of the battery (if you cant get a scan tool) maybe some lucas fluid with a filter change then drop the valve body and clean it up.
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline LTZ C20

  • Senior Member
  • ****
  • Posts: 3795
  • "I'm here for a good time" -George Strait
Re: '06 Buick Lucerne transmission issue
« Reply #12 on: July 13, 2016, 09:30:58 AM »
Then your best bet is to take it to a dealer. It may seem like you don't want too but only they have the knowledge to fix those. I don't recommend using an independent shop.
LTZ Cheyenne C20

Offline Irish_Alley

  • Tim
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13319
  • Family is not an important thing. It's everything.
Re: '06 Buick Lucerne transmission issue
« Reply #13 on: July 13, 2016, 09:41:35 AM »
and dont let them talk you into a flush. its a waist of money and GM put out a TSB about not doing a flush and the only thing they say to flush is the transmission cooler when youre replacing the whole trans cause the old one crapped out
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7543
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: '06 Buick Lucerne transmission issue
« Reply #14 on: July 13, 2016, 09:44:42 AM »
and dont let them talk you into a flush. its a waist of money and GM put out a TSB about not doing a flush and the only thing they say to flush is the transmission cooler when youre replacing the whole trans cause the old one crapped out

Good to know, thanks for the heads up
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/