6l80E clunk when coasting shift to 2nd
Aug 26, 2011 | 09:50 PM
#12
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From: Little Elm, TX
i rode with him the other night to see what it's doing and this truck DEFINITELY has a stock tune. the once or twice i kind of heard it sounds like a little extra backlash in the rearend or transfer case. has that loose mechanical sound
i gotta say jeff, it's pretty dang minor and i would just drive the truck until it becomes more noticeable or just take it to a dealer but i doubt they'll find any problem as it sits now
i gotta say jeff, it's pretty dang minor and i would just drive the truck until it becomes more noticeable or just take it to a dealer but i doubt they'll find any problem as it sits now
Aug 27, 2011 | 12:00 PM
#13
#99-04-20-002G: Information on Driveline Clunk Noise when Shifting Between PARK and DRIVE, PARK and REVERSE or DRIVE and REVERSE - (May 6, 2011)Subject: Information on Driveline Clunk Noise When Shifting Between PARK and DRIVE, PARK and REVERSE or DRIVE and REVERSE
Models: 2012 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn)
2010 and Prior HUMMER H2, H3
2009 and Prior Saab 9-7X
--------------------------------------------------------------------------------
This bulletin is being revised to add current model years. Please discard Corporate Bulletin Number 99-04-20-002F (Section 04 - Driveline/Axle).
--------------------------------------------------------------------------------
Important: The condition described in this bulletin should not be confused with the following previous bulletins:
• Info - Discontinue Flushing and Replacing Transfer Case Fluid Due to Bump/Clunk Concern (Corporate Bulletin Number 99-04-21-004A)
• Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke) (Corporate Bulletin Number 01-04-17-004B)
• Clunk Noise at Stop or From Launch (Clean/Lubricate Rear Propshaft Slip Yoke Splines) (Corporate Bulletin Number 09-04-21-003D)
• Bump Feel/Clunk Noise at Stop or From Launch (Clean/Lubricate Propeller Shaft Slip Yoke Splines) (Corporate Bulletin Number 09-04-17-002E)
Some customers of vehicles equipped with automatic transmissions may comment that the vehicle exhibits a clunk noise when shifting between Park and Drive, Park and Reverse, or Drive and Reverse. Similarly, customers of vehicles equipped with automatic or manual transmissions may comment that the vehicle exhibits a clunk noise while driving when the accelerator is quickly depressed and then released.
Note: Compare this complaint vehicle to a like vehicle. If the results are the same, this is a normal condition. For additional diagnostic information, refer to the appropriate Service information.
Whenever there are two or more gears interacting with one another, there must be a certain amount of clearance between those gears in order for the gears to operate properly. This clearance or freeplay (also known as lash) can translate into a clunk noise whenever the gear is loaded and unloaded quickly, or whenever the direction of rotation is reversed. The more gears you have in a system, the more freeplay the total system will have.
The clunk noise that owners sometimes hear may be the result of a buildup of freeplay (lash) between the components in the driveline.
For example, the potential for a driveline clunk would be greater in a 4-wheel drive or all-wheel drive vehicle than a 2-wheel drive vehicle. This is because in addition to the freeplay from the rear axle gears, the universal joints, and the transmission (common to both vehicles), the 4-wheel drive transfer case gears (and their associated clearances) add additional freeplay to the driveline.
In service, dealers are discouraged from attempting to repair driveline clunk conditions for the following reasons:
• Comments of driveline clunk are almost never the result of one individual component with excessive lash, but rather the result of the added affect of freeplay (or lash) present in all of the driveline components.
Because all of the components in the driveline have a certain amount of lash by design, changing driveline components may not result in a satisfactory lash reduction.
• While some owners may find the clunk noise objectionable, this will not adversely affect durability or performance.
• For additional diagnostic information, refer to the appropriate Service Information.
Models: 2012 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn)
2010 and Prior HUMMER H2, H3
2009 and Prior Saab 9-7X
--------------------------------------------------------------------------------
This bulletin is being revised to add current model years. Please discard Corporate Bulletin Number 99-04-20-002F (Section 04 - Driveline/Axle).
--------------------------------------------------------------------------------
Important: The condition described in this bulletin should not be confused with the following previous bulletins:
• Info - Discontinue Flushing and Replacing Transfer Case Fluid Due to Bump/Clunk Concern (Corporate Bulletin Number 99-04-21-004A)
• Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke) (Corporate Bulletin Number 01-04-17-004B)
• Clunk Noise at Stop or From Launch (Clean/Lubricate Rear Propshaft Slip Yoke Splines) (Corporate Bulletin Number 09-04-21-003D)
• Bump Feel/Clunk Noise at Stop or From Launch (Clean/Lubricate Propeller Shaft Slip Yoke Splines) (Corporate Bulletin Number 09-04-17-002E)
Some customers of vehicles equipped with automatic transmissions may comment that the vehicle exhibits a clunk noise when shifting between Park and Drive, Park and Reverse, or Drive and Reverse. Similarly, customers of vehicles equipped with automatic or manual transmissions may comment that the vehicle exhibits a clunk noise while driving when the accelerator is quickly depressed and then released.
Note: Compare this complaint vehicle to a like vehicle. If the results are the same, this is a normal condition. For additional diagnostic information, refer to the appropriate Service information.
Whenever there are two or more gears interacting with one another, there must be a certain amount of clearance between those gears in order for the gears to operate properly. This clearance or freeplay (also known as lash) can translate into a clunk noise whenever the gear is loaded and unloaded quickly, or whenever the direction of rotation is reversed. The more gears you have in a system, the more freeplay the total system will have.
The clunk noise that owners sometimes hear may be the result of a buildup of freeplay (lash) between the components in the driveline.
For example, the potential for a driveline clunk would be greater in a 4-wheel drive or all-wheel drive vehicle than a 2-wheel drive vehicle. This is because in addition to the freeplay from the rear axle gears, the universal joints, and the transmission (common to both vehicles), the 4-wheel drive transfer case gears (and their associated clearances) add additional freeplay to the driveline.
In service, dealers are discouraged from attempting to repair driveline clunk conditions for the following reasons:
• Comments of driveline clunk are almost never the result of one individual component with excessive lash, but rather the result of the added affect of freeplay (or lash) present in all of the driveline components.
Because all of the components in the driveline have a certain amount of lash by design, changing driveline components may not result in a satisfactory lash reduction.
• While some owners may find the clunk noise objectionable, this will not adversely affect durability or performance.
• For additional diagnostic information, refer to the appropriate Service Information.
Sep 20, 2011 | 05:21 PM
#14
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Joined: Aug 2008
Posts: 141
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From: UAE
I had this problem before ,check the engine mounting they might be broken for the new gmt900 broken engine mounts is commen i replaced them twice in 5 years and the transfer case could be also the problem i also got a broken transfer case replaced with a used one .
Jan 6, 2012 | 01:35 PM
#15
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Joined: Jan 2012
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im not alone!
Have you found a solution for this? Driving home in traffic two days ago i had 7 instances within 4 miles where shifting from 1st to 2nd i experienced a VERY loud metalic clank and whiplashing jolt. RPM's were between 1500 and 2k at time of shift due to traffic driving which I do every day. I tried gassing it and it shifted smooth, then the next cruising shift was rough again. Noticed a bump (more than normal) on the downshift to first as well. Of course the next day it drove to the dealer shifting like butter. Go figure.
New Trans installed 6 months ago after original trans blew out 4th gear at 50k (very light use). Also just got rear ended hard enough to slightly bend the frame at the bumper. Thinking the yoke needs to flipped per TSB???
I have also noticed an intermittent lunging when stopped at a light (usually withing first 5 stops in the AM coldish engine / prob not trans since it happened with old and new). My truck (2007 Sierra 1500 4x4 NBS) is at rest for at least 10 seconds, in drive. idle is normal.. then all of a sudden it bumps forward as if I was slightly rear-ended. I dont notice an rpm spike. Deal cant reproduce so they've never offered any advice.
Any suggestions would be amazing! Thanks guys!
New Trans installed 6 months ago after original trans blew out 4th gear at 50k (very light use). Also just got rear ended hard enough to slightly bend the frame at the bumper. Thinking the yoke needs to flipped per TSB???
I have also noticed an intermittent lunging when stopped at a light (usually withing first 5 stops in the AM coldish engine / prob not trans since it happened with old and new). My truck (2007 Sierra 1500 4x4 NBS) is at rest for at least 10 seconds, in drive. idle is normal.. then all of a sudden it bumps forward as if I was slightly rear-ended. I dont notice an rpm spike. Deal cant reproduce so they've never offered any advice.
Any suggestions would be amazing! Thanks guys!
Jan 6, 2012 | 01:41 PM
#16
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From: Little Elm, TX
Have you found a solution for this? Driving home in traffic two days ago i had 7 instances within 4 miles where shifting from 1st to 2nd i experienced a VERY loud metalic clank and whiplashing jolt. RPM's were between 1500 and 2k at time of shift due to traffic driving which I do every day. I tried gassing it and it shifted smooth, then the next cruising shift was rough again. Noticed a bump (more than normal) on the downshift to first as well. Of course the next day it drove to the dealer shifting like butter. Go figure.
New Trans installed 6 months ago after original trans blew out 4th gear at 50k (very light use). Also just got rear ended hard enough to slightly bend the frame at the bumper. Thinking the yoke needs to flipped per TSB???
I have also noticed an intermittent lunging when stopped at a light (usually withing first 5 stops in the AM coldish engine / prob not trans since it happened with old and new). My truck (2007 Sierra 1500 4x4 NBS) is at rest for at least 10 seconds, in drive. idle is normal.. then all of a sudden it bumps forward as if I was slightly rear-ended. I dont notice an rpm spike. Deal cant reproduce so they've never offered any advice.
Any suggestions would be amazing! Thanks guys!
New Trans installed 6 months ago after original trans blew out 4th gear at 50k (very light use). Also just got rear ended hard enough to slightly bend the frame at the bumper. Thinking the yoke needs to flipped per TSB???
I have also noticed an intermittent lunging when stopped at a light (usually withing first 5 stops in the AM coldish engine / prob not trans since it happened with old and new). My truck (2007 Sierra 1500 4x4 NBS) is at rest for at least 10 seconds, in drive. idle is normal.. then all of a sudden it bumps forward as if I was slightly rear-ended. I dont notice an rpm spike. Deal cant reproduce so they've never offered any advice.
Any suggestions would be amazing! Thanks guys!
Is your sierra a denali? I can't get mine to "make it" clank either. But it's EXACTLY what you're saying it does. Mine also has the "slip" from 1st to 2nd as if it were a manual transmission. Sometimes 2nd to 3rd also. I need to put it in the shop.
Jan 6, 2012 | 03:07 PM
#17
On The Tree
Joined: Jan 2012
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From: Newport Beach, CA
^ My ’11 2WD has done this intermittently since new (~1200 miles currently).
Save for that annoying trait, it’s a damn sight better than our previous 700R4/4L60 it replaced.
Intend to document with the service manager just in case it’s a symptom of impending -premature- failure.
Won’t be surprised when he regurgitates the “it’s normal” disclaimer though.
Makes a TM tune all the more appealing. ;)
Save for that annoying trait, it’s a damn sight better than our previous 700R4/4L60 it replaced.
Intend to document with the service manager just in case it’s a symptom of impending -premature- failure.
Won’t be surprised when he regurgitates the “it’s normal” disclaimer though.
Makes a TM tune all the more appealing. ;)
Jan 7, 2013 | 09:27 PM
#19
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Joined: Jan 2012
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From: Newport Beach, CA
Recently eclipsed the 20,000 mile threshold with mine.
Somewhat counterintuitively, reducing torque management and increasing line pressure virtually eliminated this ‘confused’ shifting characteristic.
Somewhat counterintuitively, reducing torque management and increasing line pressure virtually eliminated this ‘confused’ shifting characteristic.
Sep 22, 2013 | 01:55 PM
#20
I know this thread is old but I've been dealing with this since the truck was new (38k miles now). It seems the truck didn't do it as much when it was tuned. But now that the tune is off it feels worse than ever. It's such a horrible feeling With the loud metal clunk, sometimes I think my transmission is gonna fall out haha. It sucks when my new truck is louder going into park than my friends ragged out GTO with 170k on it.
I have gotten under the truck and rotated the drive shaft back and forth and it seems the slack is all forward right at the tail shaft section of the trans. It has a lot of play. I guess I will take it to the dealer and see what they will do.
I have gotten under the truck and rotated the drive shaft back and forth and it seems the slack is all forward right at the tail shaft section of the trans. It has a lot of play. I guess I will take it to the dealer and see what they will do.