NemesisC5

Today I was returning from my lunch out and decided to punch it from a slow roll and felt the tranny slip around 4k rpm and it flashed to redline. I immediatley let off but too late so I coasted as far as it would take me luckily less than a mile from home. As I coasted to a stop I put it into park and checked my tranny temp and it was a cool 160* so no problem there. I turned the truck off then restarted and still no forward drive, it feels like neutral with the exception of maybe 25-50rpm drop barely noticeable on tachometer needle. Since I was near home I put it in reverse and drove home around the block.

Next, in my driveway I called OnStar for vehicle diagnostic report and they said that there was no evidence showing of any malfunction with no codes registering. I reinstalled my stock tune from my Diablosport inTune and will have it towed to dealership Monday for diagnostics. I'm hoping & praying I will get lucky and somehow they will fix under the 100k powertrain warranty but I don't expect good fortune to be on my side. The truck has 63k miles and has been a great driver......sure hope the aftermarket tune was not the cause of the failure. I'll report my findings hopefully Monday, and hopefully the news won't be sickening

Bit

iTrader: (1)

Sorry to tell you but the last truck that came to the dealership with these problems, we put a tranny in it. I tore the bad one down to find out the problem and perform a cost cap. It a lot of stuff burnt up, but the only reason it had reverse was because the reverse clutches where welded together. It was cheaper to put a new unit in than to fix the bad one.

NemesisC5

Do you remember what the bill was ? $ ?

What caused the problem? Was it covered under warranty?

Bit

iTrader: (1)

I have no clue what caused it. There where a few codes for excessive slippage but the customer said he never felt it, just one day wouldn't go forward.

I do remember the deeper we got the better the parts looked. All the damage was in the front part of the tranny.

I think the total for parts was like $1800 so GM just sent a new one. It was warranty.

AUTOT3K

iTrader: (3)

have you checked the fluid?
chances are the trans is toast but you'll definitely know by the smell of the fluid
it'll be covered under warranty, your pretty far off the 100k mark!

silverado6.2

Will they be able to detect a past ecm flash?

NemesisC5

Used my OnStar "drivers assistance" or vehicle transport service today to have the truck delivered to the dealership I purchased it from 5 miles from my driveway. Nothing done today except test drive which couldn't have gone far and checked for codes which it showed no codes. Tomorrow they will remove transmission and open it up. I'll report back with what I find out.

On another note they provided me a loaner 2014 Silverado 5.3L from their rental fleet. Truck is refined in every way, drives smoothly and quietly almost like a car with upscale interior design and features. Power was nothing to make me smile but it likely has the 3.08 diff gear.

Also, to answer AUTOT3K I did not check the fluid for smell but I will likely hear tomorrow if it is burnt.

gonzo 6.2

iTrader: (8)

hope it sailes through for a replacement trans and your up and running by the end of the week.
With a million members here is this one the first 6L80e fail with a near stock truck?

gonzo 6.2

iTrader: (8)

Memesisc5
Your a long time LS guru here.What are you doing with a diablow? you should know better than that.

My buddy learned his lesson the hard way in 07

NemesisC5

Convenience played a big part because of my work schedule. I don't have any evidence to attribute the failure to the Diablosport product especially since GM issued service bulletins documenting this issue with 6L80E trannies. I did a search and found similar failures on trucks tuned by well known mail order tuners so I don't want to point fingers. All that being said I just hope it gets through the system and will be covered by warranty. Possibly later today I will have some feedback from the dealership.

On a follow up to my experience in the 2014 loaner with 5.3L it seems to have loosened up a little after I likely drove it harder than previous drivers. The throttle response & torque definitely feel better today than yesterday.