2019 Silverado Z-71 Trail Boss transmission issues, continued...

[wahoowad]

Bought new 2019 Z-71 Trail Boss with 5.3L back in late 2019. A year later I took it to a GM dealer because it was exhibiting the 'delayed engagement with clunk' issue reported by many, but dealer said they could not replicate the issue. It has continue to do it but I just baby it coming out of reverse and lived with it. Over time the transmission went from being otherwise smooth to being less smooth, and now it's making a moderately hard shift going into gear and sometimes automatic shifts during acceleration are more noticeable.

 

My non-dealer repair shop says the transmissions on these are failing left and right. Pretty sure in on year 4 of a 5 year drivetrain warranty (I haven't confirmed this yet), I only have 45k miles and want to take it back to dealer to get them to assess the transmission. Are there any specific service bulletins that I should reference to help me with warranty repairs?

[Rail Boss]

Same Truck, same shifting issues, with the addition of hunting or cant decide what gear to be in between 35 and 47mph at steady cruise and especially light acceleration in that speed range. Add to that occasional HARD downshift when coming to a stop. Also extended shift time/ slow shift between either 1st and 2nd or 2nd and 3rd. 2019 Custom Trail Boss Z71 5.3l 6spd trans. 35,798mi.  Recall reading something about transmission fluid causing this back when it first started, now its getting worse. Possibly a TSB. If I find it I will add it to this post. I am not sure whether or not changing the transmission fluid has fixed this problem for anyone though??

[wahoowad]

Mine is the 8 speed trans.

[newdude]

On 9/28/2023 at 9:12 AM, wahoowad said:

Bought new 2019 Z-71 Trail Boss with 5.3L back in late 2019. A year later I took it to a GM dealer because it was exhibiting the 'delayed engagement with clunk' issue reported by many, but dealer said they could not replicate the issue. It has continue to do it but I just baby it coming out of reverse and lived with it. Over time the transmission went from being otherwise smooth to being less smooth, and now it's making a moderately hard shift going into gear and sometimes automatic shifts during acceleration are more noticeable.

 

My non-dealer repair shop says the transmissions on these are failing left and right. Pretty sure in on year 4 of a 5 year drivetrain warranty (I haven't confirmed this yet), I only have 45k miles and want to take it back to dealer to get them to assess the transmission. Are there any specific service bulletins that I should reference to help me with warranty repairs?

 

 

6 speed failure rate is bad.  8 speeds fail much less so I'm somewhat surprised your transmission shop says the 8s are going left and right when in dealer land its the opposite.

 

Reverse to Drive clunk - READ HERE 20-NA-102 1..2 (nhtsa.gov)

 

1-2 harsh shift - READ HERE temp.xml (nhtsa.gov)

 

The only thing for sure they could do that might resolve some of your issues is a fluid change.  Here's the bulletin on 8 speed shudder for 2019 - 19-NA-121 1..6 (nhtsa.gov)

 

3 hours ago, Rail Boss said:

Same Truck, same shifting issues, with the addition of hunting or cant decide what gear to be in between 35 and 47mph at steady cruise and especially light acceleration in that speed range. Add to that occasional HARD downshift when coming to a stop. Also extended shift time/ slow shift between either 1st and 2nd or 2nd and 3rd. 2019 Custom Trail Boss Z71 5.3l 6spd trans. 35,798mi.  Recall reading something about transmission fluid causing this back when it first started, now its getting worse. Possibly a TSB. If I find it I will add it to this post. I am not sure whether or not changing the transmission fluid has fixed this problem for anyone though??

 

 

Not the "same" truck since OP has an 8 speed and you've got the 6 speed.  

 

Fluid causing issues is the 8 speed.  

 

2-3 shift flare is normal on the 6 speed.  Bulletin - 22-NA-185 1..3 (nhtsa.gov)

 

Other shift concerns - MC-10226384-9999.pdf (nhtsa.gov)

Edited September 29, 2023 by newdude

[MrMagloo]

Hey New Dude, is there a place where you can search for SB on the NHTSA site?  I was trying to see if I could get a copy of all SB's for the 2023's but I'm striking out?  Clearly the maintain them, but cannot seem to access unless someone posts a link?

 

*** On Edit, finally figured out that you cannot enter a VIN. You must use the Vehicle Tab.  Thx!

Edited September 29, 2023 by MrMagloo

[wahoowad]

Thanks @New Dude!

 

Your info about "Here's the bulletin on 8 speed shudder for 2019 - 19-NA-121 1..6 (nhtsa.gov)" matches my issue.

 

How can I determine if my truck meets this date criteria?

 

[newdude]

2 hours ago, wahoowad said:

Thanks @New Dude!

 

Your info about "Here's the bulletin on 8 speed shudder for 2019 - 19-NA-121 1..6 (nhtsa.gov)" matches my issue.

 

How can I determine if my truck meets this date criteria?

 

 

 

Look for the build date in your driver's door jamb.  Should be printed on one of the silver stickers.  

[Stephanie Borte]

WE had the same issues with our 2019 Trail Boss. It was in and out of the dealership0 numerous times for my husband explained it felt like the transmission was slipping. After about 6 times and the dealership dragging their feet. Stating they could never see an issue. IT now has 89k miles and it left on a flat bed today  and needs a new transmission. Of course the dealership cant even look at it for 4 weeks. We are livid.