And update for the better? Clunk be gone?

crushNchowda · December 7, 2015

My issue was a shift flare from 2nd to 3rd gear shift after a short shut down of a warm engine, and normally would only happen once, but on a few occasions it did happen on the second 2/3 shift after a quick stop and no shutdown.

It started around 10,000 miles on the odometer i believe so by 13,000 I had in in and dealer said they could not replicate.

I was contacted by a GM Customer Rep and was asked if I would take to another dealer for a second opinion, and I agreed. They again, because the truck sat for 57 minutes on a cool day, could not replicate, but did advised that it is one of two things wrong, electronic or hydraulic. They replaced the TCM and inspected and cleaned valve body, changed filter and fluid, but that did not take care for the issue. That was the cheaper of the 2 fixes and I always prefer to try the cheaper fix first before going to the higher cost fix.

Back to original dealer and it just so happened that they just repaired a similar transmission that had the same symptoms. I agreed to wait and see how that trans reacted to their work and after a week or 10 days the owner reported the problem was solved.

The dealer agreed to do the 3,5.R clutch pack replacement on mine and afterwards I have not had any issues whatsoever.

I still had the "confusion" trans shifting as I tried to explain in earlier posting in this thread, but that was greatly improved with the transfer case update that is being discussed in this thread.

not sure if I posted in this thread previously - but this is THE EXACT same TSB that was issued way back in '07-09 for 6L80 equipped vehicles - my Pontiac G8 GT had it done, HOW CAN IT BE POSSIBLE THAT GM WOULD STILL USE DEFECTIVE TRANSMISSIONS KNOWING THIS!!!!!!!!

hemipowered22z · December 8, 2015

I had this same recall or whatever performed on my truck and I feel like the shifting has gotten worse. No my truck is lifted and I use a programmer as well I was wondering if it was the new software load from GM or maybe the way it interacts with the tune from my programmer. I think im gonna take the tune out and see what it does.

No Tyme · December 9, 2015

not sure if I posted in this thread previously - but this is THE EXACT same TSB that was issued way back in '07-09 for 6L80 equipped vehicles - my Pontiac G8 GT had it done, HOW CAN IT BE POSSIBLE THAT GM WOULD STILL USE DEFECTIVE TRANSMISSIONS KNOWING THIS!!!!!!!!

Well there wasn't any TSB for my issue, or at least none that I know of. I just stated to the GM customer rep and my dealer that these same transmission are built 10 miles from my house and knowing a few of the guys that build them, they said it was a known issue. It may only be 1 in 500 but the flare shift isn't something new.

I believe that my truck, being a Crew Cab is from south of the boarder, and I think they make the tyranny down their also... Just haven't confirmed that yet.

I had this same recall or whatever performed on my truck and I feel like the shifting has gotten worse. No my truck is lifted and I use a programmer as well I was wondering if it was the new software load from GM or maybe the way it interacts with the tune from my programmer. I think im gonna take the tune out and see what it does.

I can tell you for a fact that the "confusion" that once came from transmission is no more. If you were looking for quicker shifts I don't think the update would change anything there...

When you say "feel like the shifting has gotten worse" can you elaborate?

JUSTINASS · December 15, 2015

had my seat cover replaced and they did this 15304 at the same time...much improved shift points...

that lag or fall on it face feel from 20-30 gone.

and i waited while they did it...not like i dropped it off and picked it up days later to skew my judgement

Z45 · December 15, 2015

I believe that my truck, being a Crew Cab is from south of the boarder, and I think they make the tyranny down their also... Just haven't confirmed that yet.

The 8L90 is only built in Toledo Ohio USA.

Mexico 1500 crew cabs will have a '3' as the first digit in the VIN.

Flint 1500 crew cabs with have a '1' as the first digit in the VIN.

WhineyTTwins · December 15, 2015

So i have had the update for almost 2 months. At first, the truck shifted much smoother and was less sluggish. Now, the truck seems worse than before. The transmission is about as indecisive as my girlfriend choosing what she wants to eat. Slamming gears is back and up shifts and downshifts when it shouldn't. I am even getting hang between shifts sometimes and that never use to happen. If this is like my BMW, then the car is adaptive and learns as you drive and this can be troublesome if the software is not efficient. I'm going to take it back and have them reformat everything.

Coppertone · December 15, 2015

So i have had the update for almost 2 months. At first, the truck shifted much smoother and was less sluggish. Now, the truck seems worse than before. The transmission is about as indecisive as my girlfriend choosing what she wants to eat. Slamming gears is back and up shifts and downshifts when it shouldn't. I am even getting hang between shifts sometimes and that never use to happen. If this is like my BMW, then the car is adaptive and learns as you drive and this can be troublesome if the software is not efficient. I'm going to take it back and have them reformat everything.

This is exactly how mine drives....pre and post TC update. It shifts like the transmission is filled with molasses. It's laughable at what it does when I slow down on the highway (when someone is turning off) and then accelerate. It doesn't know what the hell it needs to do. "Shift, lag, shift again, stutter, clunk, accelerate" is how it usually goes.

Sent from my iPhone using Tapatalk

WhineyTTwins · December 15, 2015

This is exactly how mine drives....pre and post TC update. It shifts like the transmission is filled with molasses. It's laughable at what it does when I slow down on the highway (when someone is turning off) and then accelerate. It doesn't know what the hell it needs to do. "Shift, lag, shift again, stutter, clunk, accelerate" is how it usually goes.

Sent from my iPhone using Tapatalk

Yep, just like that. Really is one of the worst transmissions or transmission software i have ever come across. I prefer my old Lightning with a shift kit over this. At least that one only up shifted hard but it was always on point with downshifts and shift points.

No Tyme · December 15, 2015

The 8L90 is only built in Toledo Ohio USA.

Mexico 1500 crew cabs will have a '3' as the first digit in the VIN.

Flint 1500 crew cabs with have a '1' as the first digit in the VIN.

Thanks for the info on the vin number... Unfortunately that confirms I have a "beaner" truck. LOL

As for the trans I have the 6 speed, 6L80. They are still built in Toledo.

redwngr · December 15, 2015

The 8L90 is only built in Toledo Ohio USA.

Mexico 1500 crew cabs will have a '3' as the first digit in the VIN.

Flint 1500 crew cabs with have a '1' as the first digit in the VIN.

GM powertrain document has info is conflicting.

On the 2016 product guide summary page it shows the 8L90 assembled in both Toledo OH and Silao, Mexico.

http://gmpowertrain.com/product_guide/2016_Information_Guide_20151030.pdf

On the 'specs' page the 8L90 it says it assembled in Toledo.

No Tyme · December 16, 2015

GM powertrain document has info is conflicting.

On the 2016 product guide summary page it shows the 8L90 assembled in both Toledo OH and Silao, Mexico.

http://gmpowertrain.com/product_guide/2016_Information_Guide_20151030.pdf

On the 'specs' page the 8L90 it says it assembled in Toledo.

They have been building the 8 speed in Toledo for the Corvette for a while... I would have to ask because I am not in there... But as I stated I wasn't sure if my 6L80 was built in Toledo or Mexico. If I remember correctly there should be something on the trans itself to confirm it's assembly plant..

GsBowtie · December 16, 2015

My truck has also reverted back to very poor transmission shifting. My truck shifts WAY to early and on my back roads commute it's constantly lugging the engine at 1,000 or so rpm, even when trying to climb hills it does not want to down shift.

I've also noticed in the morning when cold iit seems to shift harder than it usually does. It also makes a noise at times when the engine is lugging.

With this poor transmission programming I'm very concerned about the longterm longevity of both the engine and trans.

My 2004 cavalier with 142,000 miles shifts way better than my new 50k truck! I also still have the occasional downshift clunk too!

Gm please address this!

Steeks · December 17, 2015

This is what I've noticed (above comment) in the morning it starts off confused or shifting hard in cold wheather. Once warmed up seems fine tho. My build date is 10/15 with the 8 speed and 6.2 just wondering if this is the start of a headache it only has 2500 miles on it

DPetry94 · December 20, 2015

So has everyone's shifting gone back to how it was before the update? It sounded like it was going to help a lot, but if it doesn't last then I won't even bother.