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Rebound
01-17-2008, 09:01 PM
Hello all - new member here, with an '07 Tahoe LT3.

I only have one complaint - ever since I bought my Tahoe (in March), the transmission has "surged" when under light acceleration.

It normally only happens above 45 MPH or so. When I give it a little gas, you can feel the truck surging, see it on the tach, and hear the engine surging.

Anyone else have this problem? The stealer "couldn't replicate the problem." Go figure. I'm kicking around taking a tech for a ride so he can see/feel it for himself.

johnebgoode
01-18-2008, 06:23 PM
Surging.....do you mean the tach is going up but truck wont accelerate?

Rebound
01-18-2008, 10:15 PM
Surging.....do you mean the tach is going up but truck wont accelerate?

Up and down.

johnebgoode
01-19-2008, 04:36 PM
Up and down.

If the truck is gaining and losing rpm's while the gas pedal is depressed there is a possibility Trans can be slipping. How many miles on your rig ?
Pull dip stick and smell fluid. Does it have a burned odor? Does it look red or brownish? Brownish color indicates a problem. If still under warranty I would definately bring it to dealer, even though we all cringe at the idea.
Only other possibility is there may be a problem with the TCM. But again, a trip to the dealer may be warranted.
This is all based on me comprehending your problem correctly.

Rebound
01-19-2008, 10:01 PM
Like I said, when I accelerate slightly (not enough to kick it down a gear - also usually when it's 45 MPH+), it'll gain & lose RPM's. Not 1000 RPM, but a swing of 50-150 RPM. It'll continue to do that until I either give it enough gas to kick it down, or let off the gas.

I've got 25k miles on it, and I have already taken it to the local $tealer. Their answer? The dreaded "cannot reproduce customers concern." I think I'll stop in and take a mechanic for a ride so they can see what the hell I'm talking about.

brodg
01-20-2008, 08:04 AM
Document ID# 2040065
2007 Chevrolet Tahoe - 4WD


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Subject: L76 4L70-E Chuggle, Surge, Hesitation May Be Felt with Active Fuel Management System Cylinder Deactivation Transition from V8 Mode to V4 Mode or Harsh 1-2 Upshift (Reprogram ECM and TCM) #07-06-04-013A - (11/26/2007)



Models: 2007 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007 GMC Sierra, Yukon, Yukon XL

with Active Fuel Management System Vortec® GEN IV 6.0L V8 Engine (VIN Y -- RPO L76)

and HYDRA-MATIC® 4L70-E Transmission (RPO M70)




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This bulletin is being revised to remove the 4L60-E transmission and add condition information. Please discard Corporate Bulletin Number 07-06-04-013 (Section 06 -- Engine/Propulsion System).


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Condition
Some customers may comment on a chuggle, surge or hesitation felt during an Active Fuel Management System (AFM) cylinder deactivation transition point or a harsh 1-2 upshift .

Correction
Before reprogramming the ECM and TCM, compare the vehicle to a like vehicle. This may be a normal condition for an Active Fuel Management System equipped vehicle and no repairs should be attempted. The vehicle you are evaluating may be a little harsh in AFM transition. A calibration update was released for the ECM and TCM to soften the feel of the AFM transition.

SPS Information
• Refer to Service Bulletin Number 06-08-47-001C for information on reprogramming two modules.

• ECM -- New calibration to address customer concern of bump during active fuel management transitions. Must also program TCM with latest calibrations.

• TCM -- New operating system and calibrations to improve engine performance and shift quality. You must also program the ECM with latest calibrations.

Reprogram the ECM and TCM with the latest calibrations if the above concern is encountered. Updated ECM and TCM calibrations are now available to address this concern. These calibrations, or any that follow, are designed to address this concern. Refer to Service Programming System (SPS) using the appropriate Service Information (SI) procedures. The new ECM and TCM calibrations will be available to dealerships as part of TIS2000 incremental satellite update version 4.5, for 2007 (available on 04/23/07), and on TIS DVD version 5.0/2007 or later, which will be mailed to dealers on 05/09/2007. If you cannot access the calibration, call the Techline Customer Support Center and it will be provided. As always, make sure your Tech 2® is updated with the latest software version.

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

J7716*
Modules, Powertrain Control - Engine And Transmission Control - Transmission Reprogramming with SPS
0.6 hr

Add:
Diagnostic / Drive Time
0.4 hr

*This labor operation number is for bulletin use only. This number will not be published in the Labor Time Guide.




GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


© Copyright General Motors Corporation. All Rights Reserved.


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Document ID# 2040065
2007 Chevrolet Tahoe - 4WD

fco_gonzo
01-20-2008, 09:59 AM
BRODG
you are very helpful, hang out more often.

Rebound
01-20-2008, 02:56 PM
Thanks for the bulletin! I don't have the 6.0L, but I'll throw this in front of the $tealer anyway, and see what they say.

Mucho appreciado!

Gambler
01-20-2008, 03:18 PM
Document ID# 2040065
2007 Chevrolet Tahoe - 4WD
Models: 2007 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007 GMC Sierra, Yukon, Yukon XL with Active Fuel Management System Vortec® GEN IV 6.0L V8 Engine (VIN Y -- RPO L76) and HYDRA-MATIC® 4L70-E Transmission (RPO M70)


Either there is a mistake here (no 2007 tahoe has the 6.0L engine), or this is in reference to all Tahoes and only the GMCs with the 6.0L. Any thoughts??

johnebgoode
01-20-2008, 04:13 PM
Either there is a mistake here (no 2007 tahoe has the 6.0L engine), or this is in reference to all Tahoes and only the GMCs with the 6.0L. Any thoughts??

I spotted that also.
Tahoe = 5.3

Slammed
01-20-2008, 04:44 PM
Hey next time you take a ride dont put it in OVERDRIVE just drive and come back here and thank me that the surging is gone

johnebgoode
01-20-2008, 05:21 PM
Hey next time you take a ride dont put it in OVERDRIVE just drive and come back here and thank me that the surging is gone

But will problem in OD be gone?

Rebound
01-20-2008, 10:05 PM
Exactly - the presence of a TSB means there's problem.

Putting it in 3rd just ignores the problem, it doesn't fix it. It's under warranty, they can fix it.

Slammed
01-20-2008, 10:43 PM
Listen most people think its a problem but In My Opinion I dont think it is because Overdrive should only be used after 65 MPH just like if you were driving a 5 speed in the city would you goto 5th gear??? if you did and kept down shifting all the time your arm and leg would get tired ..... Just like the automatic tranny does when it shifts into high gear at 45MPH and it will surge and feel like its skipping untill you give it more gas which makes it downshift right??? so no OD untill after 65MPH and you will be fine



But will problem in OD be gone?

Rebound
01-20-2008, 11:13 PM
In My Opinion

As you say, in your opinion.

IMHO, it is a problem, the tranny should be better programmed than that.

And yes, in my manual slushbox, I routinely shift up to the highest possible gear around town. I'm not a boy racer anymore.

brodg
01-21-2008, 06:17 AM
Document ID# 1912465
2007 Chevrolet Tahoe - 4WD


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Subject: Harsh TCC Apply Or TCC Cycling - keywords shudder surge vibration #PIP4040A - (03/05/2007)



Models: 2007 Chevrolet , Avalanche, Express, Silverado, Silverado Classic, Suburban, Tahoe, Trailblazer

2007 GMC Envoy, Savana, Sierra, Sierra Classic, Yukon, Yukon XL,

2007 Hummer H2

2007 Saab 9-7x

Equipped with 4L60E, 4L65E, 4L70E Automatic Transmission (RPO M30, M32, M70)




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This PI is being superseded to update concern and recommendation. Please discard PIP4040.


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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some customers may comment on a harsh TCC apply or TCC cycling on and off at approximately 40 - 45 MPH. This condition may occur in all V type engines in the above listed vehicles but is most likely to occur on vehicles equipped with a 4.3L, V-6 engine.

Torque converters that may experience this condition can be identified with the following P/Ns that can be found on a label stuck to the flywheel side of the torque converter.

24238892

24238894

24228895

24228898

Note: This condition has not been identified on any in-line 4, 5 or 6 cylinder engine or torque converters with any other P/N.

Recommendation/Instructions:
This condition may be caused by a mis-located seam weld on the torque converter that can warp the surface on which the converter clutch engages. This can cause a possible leak path during low apply pressure conditions.

To diagnose these conditions use a Tech 2 to monitor TCC slip speed.

• If the concern is harsh TCC apply note the slip speed when the TCC is commanded on. If the converter internal leak exists the slip speed will rapidly drop from 60-80 rpm slip to 0 rpm slip in less than one second. In a normal TCC apply the slip speed is gradually reduced over a longer period of time to provide a smooth apply.


• If the concern is TCC cycling note the slip speed after the TCC is commanded on. If the converter internal leak exits the slip speed will cycle from 0 rpm slip to 60 rpm or greater slip in regular time intervals approximately 5 - 10 seconds apart.


If either of the above slip conditions are found the torque converter weld should also be inspected. This can be done by removing the inspection hole cover on the bottom of the transmission and visually inspecting the weld. The weld should not end below an attachment lug or within 5 inches of the center of the lug, as shown See the attached illustration.

If the above conditions are found the torque converter should be replaced.

Torque converters obtained from GMSPO or with P/Ns other than those listed above may have the weld ending at or near the attachment lugs. This is acceptable and will not cause an issue.





Weld should not end under or within 5 inches either side of the center of an attachment lug

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


© Copyright General Motors Corporation. All Rights Reserved.


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Document ID# 1912465
2007 Chevrolet Tahoe - 4WD

Slammed
01-21-2008, 06:45 AM
Oh and by the way a constant upshifting and downshifting (like being in OD in the city) can also give a TCC code