Shudder/Vibration Issue

[aseibel]

1 hour ago, thom71gt said:

Based on the fact that you have a snow plow on the front, you probably do not experience the shudder as it has mainly effected vehicles in hot and humid climates where it is hot most of the time.

Is that a known fact? That's the first time I've heard it. I guess I'm lucky to live in a place where I have to shovel snow off my driveway 4 months out of the year!

 

I'd love to hear why hot, humid weather causes metal machines to shudder. Mine sure seems clunkier when I first fire it up on cold mornings.

[thom71gt]

Conditions where it is hot and humid most of the time, apparently broke down the viscosity of the fluid put in and it created a shudder in the torque tube.  Replacing the tranny fluid with the new thicker kind, eliminated this problem. I live in GA and it was exceptionally hot this year with a majority of the time it being in the 90's and the "feels like" temp over 100. I have a 16 Yukon Denali with the 8 speed and it drove like crap. Once they swapped out the fluid, it's been driving brilliantly.

[JCunningham]

ya up until 2014. then they started going downhill again.  

[Bobbie Charles]

I have a 2014 chevy silverado ltz brought new and about 5 weeks ago it started shuddering.  I have had it to 4 different garages, transmission fluid changed as well as filter.  Drove it almost 2000 miles after change and it did not shudder once.  Got home and it started shuddering really bad.  Have appt with chevy garage Friday to see what they can do.  It seems like its worse now when it tries to change gears and it is automatic.. It has less than 80,000 miles on it. Do not want to put rebuilt transmission in.  Any suggestions.

 

[huntr1117]

I honestly think the only way around the 8 speed problems is to get the trans tuned. I've had all the updates done at the dealer as far as gm tuning. I've also had the new fluid installed. It all helped but the kept acting up. I've had my tune for around 7k miles and it's great. I took my truck into the dealer about a month ago to have a recall done. Before I brought it in I took out my tuned tcm and put the stock tcm back in. I also flashed my truck back to stock. It was a night and day difference. Trans went back to being miserable to drive. As soon as I got the truck back I swapped my tcms and flashed the tune again. It's so much better.

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[Ozer]

19 hours ago, Bobbie Charles said:

I have a 2014 chevy silverado ltz brought new and about 5 weeks ago it started shuddering.  I have had it to 4 different garages, transmission fluid changed as well as filter.  Drove it almost 2000 miles after change and it did not shudder once.  Got home and it started shuddering really bad.  Have appt with chevy garage Friday to see what they can do.  It seems like its worse now when it tries to change gears and it is automatic.. It has less than 80,000 miles on it. Do not want to put rebuilt transmission in.  Any suggestions.

 

You are covered till 100k OR 5yr since production date so take it in and get a new TC or trans put in under warranty. Dont wait, your 5 year mark is coming up quickly.

Edited November 5, 2019 by Ozer

[NemesisC5]

2017 Midnight LTZ Z71 6.2 did the first triple flush and shudder never went away. Did a second triple flush and shudder returned after 3k miles. Earlier this year dealer flushed and filled with the new fluid along with re-learn on TCM. So far shudder is gone and shift performance is more responsive, feels like a new TCM tune. Service manager said I may experience rough shifts during re-learn (which I have not) but put 2k miles on and if shudder returns they will replace converter. Thus far after 1k miles all is well.

[bigman32hockey]

I'm curious what tune you were able to do on the transmission.  I was under the impression they were "locked" by GM.  

[huntr1117]

I'm curious what tune you were able to do on the transmission.  I was under the impression they were "locked" by GM.  

17 and up are locked by gm. You can have them unlocked by either sending them into hp tuners or buying an unlocked one directly from hp tuners. That's the expensive route. I found a used a tcm from a 2016 Escalade that's also a 6.2 8 speed. That tcm worked in my truck and blackbear was able to tune it. There has been other people that have tried the same thing and it wouldn't work. Blackbear doesn't know why it works for some and not others. That's why they dont advertise that specific service for 2017+. If it wouldn't have worked I would have gone the hp tuners route. I can't believe that gm wont fix the tuning but I can have someone fix it with efi live or hp tuners.

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[JCunningham]

the dealer didnt re tune his tcm they did a fast relearn on it.  

[JCunningham]

5 hours ago, Ozer said:

You are covered till 100k OR 5yr since production date so take it in and get a new TC or trans put in under warranty. Dont wait, your 5 year mark is coming up quickly.

its 5 years from date of sale to original owner not date of manufacturer. 

[JCunningham]

GM wont fix the tuning because it is mandated by the epa to get a certain mpg on paper. GM would not have put this crap tune in it if it wasnt for the epa. they are losing business because of it. 

Edited November 6, 2019 by JCunningham

[njk4o5]

16 hours ago, JCunningham said:

GM wont fix the tuning because it is mandated by the epa to get a certain mpg on paper. GM would not have put this crap tune in it if it wasnt for the epa. they are losing business because of it. 

couldnt agree more. ive never really thought of that before i just figured the guy who engineered the trans tuning was drunk when he did it

[bigman32hockey]

On 11/4/2019 at 11:18 PM, huntr1117 said:

I honestly think the only way around the 8 speed problems is to get the trans tuned. I've had all the updates done at the dealer as far as gm tuning. I've also had the new fluid installed. It all helped but the kept acting up. I've had my tune for around 7k miles and it's great. I took my truck into the dealer about a month ago to have a recall done. Before I brought it in I took out my tuned tcm and put the stock tcm back in. I also flashed my truck back to stock. It was a night and day difference. Trans went back to being miserable to drive. As soon as I got the truck back I swapped my tcms and flashed the tune again. It's so much better.

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Does the new tuned TCM fix the clunking/jerkiness, hard shifts from 1st to 2nd,etc.  I'm interested in doing this but dont want to spend the cash if it's only going to adjust shift points, etc.  Any info is great appreciated. 

[huntr1117]

Does the new tuned TCM fix the clunking/jerkiness, hard shifts from 1st to 2nd,etc.  I'm interested in doing this but dont want to spend the cash if it's only going to adjust shift points, etc.  Any info is great appreciated. 

I'm not sure what exactly Blackbear tunes in the tcm but the random hard shifts are gone. Jerkiness is gone, I'll still get a random clunk maybe once a month if that. It's pretty rare though. Probably best mod I've done to the truck as far as drivability besides fixing the gas pedal flex.

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