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Evan Whatley

2020 Sierra SLT Shudder

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Hi Everyone

 

I recently bought a new SLT sierra 5.3L and after the first week of owning it I am feeling a shudder when I accelerate from a stop. Happens every time the truck shifts from 1st to 2nd gear and feels like it is driving over rumble strips. I brought it into the dealership and they could not find a fix. GM had told them it is "normal" and that "it wont effect the longevity of the transmission". I find that very hard to believe. Has anyone had a similar experience? What was the issue and how did you fix it? 

 

Edited by Evan Whatley

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2WD with 8L90, or 4WD with 10 speed? I've been in the transmission business for 20 plus years, and if it is a transmission shudder I assure you that it is not normal, and will cause issues eventually.  If it is the 10 speed, Ford recently came out with a very expensive additive (about 70 bucks) that helps with these issues. Going off of memory right now, but I think it's called  X-16. It's a shared venture transmission, so it may help in a GM also.

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I’m chasing down a similar situation but mine is on deceleration. Have a rumble as it shifts from 3-2 from 28 to 22 miles an hr when coming to a stop. Rumbles the whole cab. I have the 8 speed and I thought it was the torque converter but the dealer thinks it’s something else and seems operating as designed.

Something I did notice is the 2 loaner trucks I had were both 8 speeds and didn’t have pinion shims and didn’t have this rumble.

Mine has pinion shims and think that’s contributing to it.


Check under the leaf springs and see if your truck has the shims, seems some trucks have them and some don’t and it’s completely arbitrary.

I’m going to pull mine out at some point this week.


Sent from my iPhone using Tapatalk

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On 5/18/2020 at 9:14 PM, Evan Whatley said:

Hi Everyone

 

I recently bought a new SLT sierra 5.3L and after the first week of owning it I am feeling a shudder when I accelerate from a stop. Happens every time the truck shifts from 1st to 2nd gear and feels like it is driving over rumble strips. I brought it into the dealership and they could not find a fix. GM had told them it is "normal" and that "it wont effect the longevity of the transmission". I find that very hard to believe. Has anyone had a similar experience? What was the issue and how did you fix it? 

 

i just made a post about this too. Ive got a trailboss 5.3 with 10 speed. Definitely have a shudder too. Noticed it from a stop light. 2nd gear and on highway. You descriptions exactly what i feel. Low rpm shudder/ feels like its on rumble strips.

First time i noticed it from a stop light i thought i had a flat tire. It didnt do it till about 1k miles 

Have a service appt for june 24th

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I have a 2019 GMC Sierra Elevation edition 5.3L with the 8 speed transmission.  I notice the hesitation/stutter every time it is driven for the first few gear cycles of the day from a stop but then the issue goes away.  I thought I read somewhere that it is because it is caused by a  lack of  fluid in a certain area of the transmission after sitting overnight and as soon as the fluid moves around it makes the stutter go away.  I just had the dealer put the new correct GM fluid in it thinking it would fix it and it did not.  I only have 9000 miles on this truck what a nightmare.

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On 5/18/2020 at 11:14 PM, Evan Whatley said:

Hi Everyone

 

I recently bought a new SLT sierra 5.3L and after the first week of owning it I am feeling a shudder when I accelerate from a stop. Happens every time the truck shifts from 1st to 2nd gear and feels like it is driving over rumble strips. I brought it into the dealership and they could not find a fix. GM had told them it is "normal" and that "it wont effect the longevity of the transmission". I find that very hard to believe. Has anyone had a similar experience? What was the issue and how did you fix it? 

 

Its the torque converter in the 8 speed. Its been an on going issue on C7 Corvettes as well. Its just a poorly designed transmission. It will have to be rebuilt most likely. IT IS NOT NORMAL GM check out the class action law suits on this transmission.

Edited by ILSilverado
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While I don't have a shudder or any operational issue with my RWD 5.3 2019 RST 8spd, I can tell you from my 50+ years experience in the transmission industry, trying to dampen any driveline noise or vibration, when your dealing with an aluminum driveshaft that's as large as the one in our trucks, is going to be a tough nut to crack!

Edited by Bobv07662
Comma added

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New 2020 Silverado. 8 speed transmission. Just started to develop a shudder from second to first on downshift when decelerating to a complete stop. Rumble strip feel. 1000 miles on truck and in for second time this week for engine light and a text message check engine/transmission in next day. So sorry I purchased this truck as I do not trust it to give me any length of service free mileage. 

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On 5/21/2020 at 1:08 PM, chadman said:

2WD with 8L90, or 4WD with 10 speed? I've been in the transmission business for 20 plus years, and if it is a transmission shudder I assure you that it is not normal, and will cause issues eventually.  If it is the 10 speed, Ford recently came out with a very expensive additive (about 70 bucks) that helps with these issues. Going off of memory right now, but I think it's called  X-16. It's a shared venture transmission, so it may help in a GM also.

Do you know if the 2 factory fluids are identical?  (Motorcraft ULV ATF and Dexron ULV AFTF)?

(would make sense to me that they would be produced by the same supplier but put in different containers)

 

As I understand it Ford did the design and has the patents, but each company did their own electronics tuning/controlling the 10R80 / 10L80 and each are doing their own manufacturing of the gearbox.

 

It's not inconceivable that one or the other has changed an additive in the ATF package. 

 

 

I find it interesting that GM uses a different fluid in each of the 6, 8 and 10 speed transmissions.  

 

6-Speed   - DEXRON-VI Automatic Transmission Fluid.
8-Speed   - DEXRON-HP Automatic Transmission Fluid.
10-Speed  - DEXRON ULV Automatic Transmission Fluid.
 

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I would have to check on that for sure, but of the top of my head I do believe they are the same.

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On 6/14/2020 at 12:36 PM, hotrodz37 said:

I’m chasing down a similar situation but mine is on deceleration. Have a rumble as it shifts from 3-2 from 28 to 22 miles an hr when coming to a stop. Rumbles the whole cab. I have the 8 speed and I thought it was the torque converter but the dealer thinks it’s something else and seems operating as designed.

Something I did notice is the 2 loaner trucks I had were both 8 speeds and didn’t have pinion shims and didn’t have this rumble.

Mine has pinion shims and think that’s contributing to it.


Check under the leaf springs and see if your truck has the shims, seems some trucks have them and some don’t and it’s completely arbitrary.

I’m going to pull mine out at some point this week.


Sent from my iPhone using Tapatalk

I have a 2020 Sierra 5.3 with 10 spd tranny and  I have the low speed shudder. Awaiting recommendations from gm pico scope findings. I really think it is a pinion angle issue

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32 minutes ago, SSsierra said:

I have a 2020 Sierra 5.3 with 10 spd tranny and  I have the low speed shudder. Awaiting recommendations from gm pico scope findings. I really think it is a pinion angle issue

 

I wound up pulling my 2 deg pinion shims that came from the factory and my issue is completely gone. My truck was at the dealer for a week them thinking it was a trans issue and then came back with "operating as designed". I ordered a digital angle finder from amazon and got to work. My operating angle was way off - no idea why my truck had shims from the factory and in the wrong direction mind you. It was quite a hassle to get them out but once I did I couldn't be happier. Measured angles afterward and everything is in spec now. Unreal GM, Unreal. 

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I don't have the issue in my 2020 Sierra SLT 8spd but I also have the revised RPO.

 

The new revised transmission was assigned RPO code MQE, replacing the M5U 8-speed unit on the half-ton Silverado and Sierra

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1 hour ago, Megalomegalodon said:

I don't have the issue in my 2020 Sierra SLT 8spd but I also have the revised RPO.

 

The new revised transmission was assigned RPO code MQE, replacing the M5U 8-speed unit on the half-ton Silverado and Sierra

MQE isn't a revised RPO, It is just the RPO that came out in the 2019 and up vehicles unless that's what you're talking about?

M5U and M5X Are 8 speeds between 2015 - 2018

 

This is the 2019 - 2020 Trouble Shooting forums so everyone here should have the MQE 8 Speed.

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37 minutes ago, carnau said:

MQE isn't a revised RPO, It is just the RPO that came out in the 2019 and up vehicles unless that's what you're talking about?

M5U and M5X Are 8 speeds between 2015 - 2018

 

This is the 2019 - 2020 Trouble Shooting forums so everyone here should have the MQE 8 Speed.

According to the article MQE replaced M5U but was a revised transmission with changes. Probably didn't fix the issue but I have not yet had it happen to me.

 

Snippet from article - https://gmauthority.com/blog/2019/06/the-gm-8-speed-transmission-just-needs-to-go-away-asap/

 

"Following a litany of complaints, GM tried to “improve” the 8-speed in the 2019 Silverado and 2019 Sierra. In a press release, the automaker said it made “enhancements designed to improve shift quality, while also adding a new centrifugal pendulum absorber torque converter” to improve smoothness. The new revised transmission was assigned RPO code MQE, replacing the M5U 8-speed unit on the half-ton Silverado and Sierra, but not (yet) on other GM products like full-size SUVs or mid-size pickups."

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