Shudder at light throttle

[Vegasmarc21]

I just went for more driving yesterday and though acceleration is better/smoother, i still can still create the shudder. Its harder to create than before but still exists. Sometimes I hear these cracks and creeks so was a little worried about a bad u joint as someone else confirmed this caused shudders while driving. Will check on that first then dr tranny here I come!

My sister in law has a 2008 Tahoe and she says her Tahoe has hesitation when slowing down for a red light then light turns green before stopping and when she accelerates it has a chuggle like hesitation....I'm thinking maybe since these Tahoes are so heavy to eliminate this, the acceleration pedal needs to be stomped on (a controlled stomp) to make it downshift to the correct gear) I'm saying this because you said you still can create the shudder which maybe just bogging....I try to just drive normal and if the sensation of bogging/ shudder comes up I stomp on it and it responses but the shudder I had was eliminated with the steps I took......it very well could be your u joints (hopefully because it's a cheap easy fix).....but that creeking sound to me might be knocking and pinging- detonation.

 

[Meccanoble]

the crack/creek sound I think is more suspension or movement related. I just changed all my plugs less than 5k miles ago and the previous ones were even good. Truck drives well other than this. In fact, I didnt notice all the extra inconsisent sounds until I swapped out my 17's for 20's. But regarding shudder, the truck went from needing to stop pushing pedal or accelerate aggressively to even get car to stop shuddering or accelerate to now where even when it shudders, it drives through the shudder. When I say I have to create the shudder, its more like I have to look for it, remembering the rpm' range and speed to create the issue.

 

[CreyCrey]

Can anyone tell me what shudder I have under very light throttle usually on any gear EXCEPT 1st and 2nd gear with about 1100 rpm to 1500 rpm..... Doesn't happen when I start driving when Tahoe is cold and not up to operating temperature. WOT there is no shudder at all. I have a 2011 Tahoe 5.3 V8 with hundred twenty thousand miles.

Recently had this issue. Dealer tried to reprogram but did not fix. They ended up replacing torque converter.

 

[Meccanoble]

Yea I truly believe torque converter replacement is the true fix but hopefully this dr tranny will improve the driving experience until converter needs to be changed. I'm hoping as long as we not out here boosting, or launching at every stop, we can get by. These issues we are experiencing could be due to a slight over or under fill on fluid that just makes the behavior different, not necessarily destroys the converter. If things were as bad as we thought, wouldnt the driving experience get worst as the transmission gets hotter? Since our issue stays consistent no matter how hot or cold tranny is, maybe we fit a better category. As you can tell, there is a lot of hope here. I just ordered dr tranny and will keep everyone posted on my experience as well.

Vegasman, still running strong right?

 

[Vegasmarc21]

Yea I truly believe torque converter replacement is the true fix but hopefully this dr tranny will improve the driving experience until converter needs to be changed. I'm hoping as long as we not out here boosting, or launching at every stop, we can get by. These issues we are experiencing could be due to a slight over or under fill on fluid that just makes the behavior different, not necessarily destroys the converter. If things were as bad as we thought, wouldnt the driving experience get worst as the transmission gets hotter? Since our issue stays consistent no matter how hot or cold tranny is, maybe we fit a better category. As you can tell, there is a lot of hope here. I just ordered dr tranny and will keep everyone posted on my experience as well.

Vegasman, still running strong right?

Yes, running strong...I felt some rough cruising....but not shudder....I repeated with brake clean on rear disc brakes at the car wash, then immediately rinsed with high pressure hose.... Tahoe seems to be running strong now again but no shudder. The doctor tranny is a good additive anyway with or without torque converter shudders. Get it and trust in it.... When I put it in it made the shudder a little bit worse but then after a day it started getting better. I am in the market when I can for new disc brakes in the back and then when I can disc brakes for the front and new pads all around. Any recommendations for inexpensive rotors that do not rust?

 

[Meccanoble]

I was going to ask you when was the last time you changed/inspected the regular brakes since you show a considerable amount of concern for them. I always went with high carbon rotors from local stores. These are considered upgrades from the basic rotors sold but not a performance rotor with the slots or drilled. They have done me well on multiple cars in multiple weather conditions from multiple local stores. I tend to go with Pepboys versions because they have best sales when I look but I'll even grab from Amazon if the price is significantly better, which it normally isnt. If the Tahoe or any other car I had was for more performance, I obviously went a different route. I didnt buy them mainly for rust but for better braking and less chance of warping. Even though the tahoe brakes descent for its size, I always felt the rotors were very small which I always connected to warping through possible over working but dont know how accurate that idea is.

 

[Doubeleive]

this is just my two cents I have been told by a very reputable transmission shop that these 6l80/6l80e's torque converter's are the #1 problem, and when they go out they take a couple other things with them but there otherwise a pretty good transmission, I haven't had any issue with mine at 95k but I did swap the oem trans cooler out for a flex a lite that fits like a love by just drilling a couple new mounting holes in the front support frame and I added a b&m deep trans pan just to be on the safe side, the trans temps are way down but the weather is cooler now as well, as far as throttle body's relearning I swapped mine out for the LS7 throttle body and it synced up almost instantly. the only thing I can feel is the afm kicking in at highway cruising speeds which I haven't disabled simply because I try to save at least little tiny bit of gas I guess, lol

 

[Meccanoble]

Not happy to hear they take out other things but I never had an issue other than this shudder. Never had high temps and I drive a lot at night on the weekends. I dont use the truck for what its true capabilities are (towing, hauling, dirt roads). I just needed the space and potential.

Can we replace with a better torque converter to avoid the issue in another 150k miles? I was hoping we can swap out entire transmission/converter from a silverado or whatever is the heaviest towing truck in the GMC family and not only avoid this issue but have a very capable tranny in case we venture into the boost/abuse world.

 

[Vegasmarc21]

I was going to ask you when was the last time you changed/inspected the regular brakes since you show a considerable amount of concern for them. I always went with high carbon rotors from local stores. These are considered upgrades from the basic rotors sold but not a performance rotor with the slots or drilled. They have done me well on multiple cars in multiple weather conditions from multiple local stores. I tend to go with Pepboys versions because they have best sales when I look but I'll even grab from Amazon if the price is significantly better, which it normally isnt. If the Tahoe or any other car I had was for more performance, I obviously went a different route. I didnt buy them mainly for rust but for better braking and less chance of warping. Even though the tahoe brakes descent for its size, I always felt the rotors were very small which I always connected to warping through possible over working but dont know how accurate that idea is.

My concern for the brakes is that the brakes pulsate when braking....Im guessing they are warped. I have not taken the wheels off, but they pulsate when braking, and also the rears stick a bit. The pads seem to be grabbing....I don't know how long ago they have been replaced, I did buy it from a reputable delership so Im guessing the pads still have life but if I'm going to change rotors, might as well change the pads so the new rotors stay true.....and adjust them for the least amount of drag....less drag on brakes equals less drag on tc clutch is what I'm thinking... And or less dragging on brakes, means the less of a chance of the torque converter locking and unlocking uncontrollably may be causing a shudder like feeling. (I might not know what I'm talking about on that one.)

That's why my formula of spraying brake clean on rotors and pressure washing along 2 tubes of the Dr shudder fix gave me that nice shudder free ride with smoother up shift and down
shifts. Try my formula...I might be crazy but at least somehow by effort or dumb luck it worked....

 

[Vegasmarc21]

this is just my two cents I have been told by a very reputable transmission shop that these 6l80/6l80e's torque converter's are the #1 problem, and when they go out they take a couple other things with them but there otherwise a pretty good transmission, I haven't had any issue with mine at 95k but I did swap the oem trans cooler out for a flex a lite that fits like a love by just drilling a couple new mounting holes in the front support frame and I added a b&m deep trans pan just to be on the safe side, the trans temps are way down but the weather is cooler now as well, as far as throttle body's relearning I swapped mine out for the LS7 throttle body and it synced up almost instantly. the only thing I can feel is the afm kicking in at highway cruising speeds which I haven't disabled simply because I try to save at least little tiny bit of gas I guess, lol

Did the LS7 throttle body help performance? Why did you swap it out for the LS7.... What are the pros and cons?