transmission issue

[econometrics]

1 minute ago, Silverado4x4 said:

Yep you have the trans shutter, mine didn't show up till around 12,000 miles so I took it in and had the trans flush with the new updated fluid and now its as smooth as butter.

 

Thanks, that's encouraging. 

[mfbearded]

did the fluid flush...immediate difference 

[BamX31]

2019 Sierra 5.3 with the 8 speed trans. At approx 14,000 miles it started slamming into 2nd from 1st and upon stopping at a red ight it would lurch when going from 2nd to 1st. Took it to the dealer with concerns. Bad valve body was the culprit so they changed valve body along with the shift solenoid and transmission fluid and filter change. Only been two days since I got it back it it seams to be shifting the way that it should be.

[milkmaster]

Mine is a new Sierra 5.3 w/8speed tranny built in June 2021.  I should already have the newest fluid right?

[SilveradoRST]

Mine was built in Feb 2019.   Only have 10,000 miles, thanks COVID.  Just waiting for shutters and shakes to bring it in for the new ATF.   Drives smooth right now.  In the back of my mind I’m hoping I got lucky and received the new ATF from factory.   But I know March 2019 was when GM switched over.  

[dgstarr63]

The new fluid started being installed in the summer of 2019.

[SilveradoRST]

7 hours ago, dgstarr63 said:

The new fluid started being installed in the summer of 2019.

Hopes dashed.  Thanks for the info.   I guess I’ll have to wait for symptoms to appear.  
 

Edit:  The TSB says the cutoff/break point is March 1,  2019.   If they only started using the new ATF in the summer at the factory, are people with build dates between March 2, 2019 to June-ish screwed?

MC-10174268-9999.pdf

Edited August 10, 2021 by SilveradoRST

[Spoogle]

My transmission was perfectly fine right up until 2 weeks ago, then it ****** the bed completely with just under 20K miles. To make matters worse the dealership had to contact GM for the parts and so far haven't got a response so they can't give me any kind of estimate as to when I'll have a truck again.

[JimCost2014]

I guess I’ll have to wait for symptoms to appear.

 

Good luck???

[Bigfoot98]

On 8/1/2021 at 11:49 AM, Wiggums said:

I have a 2019 with the 5.3 and 8-speed. I had that done too and it seems to have helped. I still have the morning clunks from cold starts, that part seems incurable.

Id still rather deal with the garage shift and minor harsh shift on a cold start over my f150 trying to activate the ejection seat while it was cold or when it felt like slipping.

[mfbearded]

Tech at dealer took for it a drive. Immediately knew it needed a flush. Got it done while I waited. I noticed an improvement immediately. Thanks everyone for the input 

[SilveradoRST]

1 hour ago, mfbearded said:

Tech at dealer took for it a drive. Immediately knew it needed a flush. Got it done while I waited. I noticed an improvement immediately. Thanks everyone for the input 

Did the symptoms (hesitation/shudder) show up one day and stay?   Or did it show up here and there and then eventually became consistent?   I had a few rumbles while cruising around 60km/h.  Happened only a couple of times.   3rd time it happened I slowed down and it went away.  But it doesn’t always happen…yet.   

[SPASierra]

Mine has had the harsh downshift in the past, but only first thing in the morning on cool days.  We were on vacation in Myrtle Beach last week and it started doing it consistently while we were in traffic.  Freaked my wife out that we would break down on the way home to PA.  I just passed 31K miles, so I guess it is time to take it to the dealer.  No idea when I will be able to get an appointment because the dealership was hit by a tornado a few weeks ago, which destroyed half of the service department building.  The other local dealer has been slammed ever since.

[Swiftks]

Enough of this... My 2019 TrailBoss w/ 8-speed goes in to local shop tomorrow and gets full flush and replacement with Amsoil Signature.  Also figured it would be a good time to swap the front and rear diff fuilds, as well as the transfer case fuild.  Will update will results after a few days of driving.

[Black02Silverado]

1 hour ago, Swiftks said:

Enough of this... My 2019 TrailBoss w/ 8-speed goes in to local shop tomorrow and gets full flush and replacement with Amsoil Signature.  Also figured it would be a good time to swap the front and rear diff fuilds, as well as the transfer case fuild.  Will update will results after a few days of driving.

Please keep us posted.  One customer I know of has had good results when he switched over to AMSOIL fluids in his 8sp.