Bit

iTrader: (1)

GM requests unit to be tore down to find problems and bad parts.

gonzo 6.2

iTrader: (8)

They dont think its a software issue? Did they flash the ECM and TCM ?

NemesisC5

Hey Gonzo, no the dealership did not look into that, mechanicals only. Repair tech said that he has had the same issue only once before out of the many he successfully repaired. He said once he contacts GM that they will instruct him to tear down again and examine the parts carefully before they will replace tranny. Knowing this, he went through entire unit carefully because they are literally NO signs of wear or dust in the pan or on filter. He will tear down again Monday morning and go through looking for something possibly missed and go from there. At least 65% of mileage has been highway and I don't beat on the truck at all. Mind you I selected the 6.2 because I wanted a faster truck and something I could tow with if needed but definitely not abused in the least.

The 2014 loaner 5.3 I've been driving has a much more refined feel to the engine and tranny both. 1-2 shift set at 5500 rpm but feels like it would rev freely past 6k if RPM limiter was not set to 5500-5600. Tried manually but it was limited. Another big thing, the 2014 NEVER kicks down a gear going over overpasses and only required kicking down going over a bridge. I believe the torque is much broader and comes on earlier in the new DI engines. I expect the 2014 6.2 will be a torque monster and a blast to drive.

01WS6/tamu

iTrader: (36)

GM used to pretty much replace failed units no questions asked. But they have gotten really chicken **** on stuff IMHO warranty isn't worth powder to blow it to hell. All they do is a half assed repair that generally works long enough to get it out of warranty. The correct way technically is a full unit replacement or complete top to bottom overhaul including a new converter for reliable long term repair. BUT all gm will authorize is replacement of failed components only for transmission repair. Unless it's completely destroyed and non savable.

My advice on warranty failures tow it in with parts in a zip lock bag and non tampered with OE programming if you want a reliable long term repair.

NemesisC5

TRANNY REPAIRED UNDER WARRANTY: Yesterday I finally got my truck back all covered under 100k drivetrain warranty. At first try since there were no signs at all of wear (clutches looked new and fluid was fresh looking without smell) the repair tech replaced the TCM. Reinstalled and nothing changed, problem remained. Next day removed and went through with a fine tooth comb. Found what is called a "piston" in parts manual but looked nothing like a piston but rather a disc that sat at bottom of clutch basket and it had a hairline crack. This crack allowed fluid to seep through and evidently could not build enough pressure for the system to work. I don't know **** about the inner workings of a tranny so if my explanation is flawed in some way please excuse and correct my words. The repair tech said this possibly could have been the result of high pressure causing a hard shift shocking the parts and causing the hairline fracture in a component that likely had a flawed casting.

View of crack in "piston"

Another view

Piston sits at bottom of this piece I called the clutch basket for no other reason than it holds I believe clutches for 1st through 4th gear


TCM, not exactly what I was expecting. Unit stays immersed in hot tranny fluid.


For what it's worth, the tranny in my 2011 is not nearly as precise and quick as the tranny in the 2014 loaner I drove for more than a week. I believe primarily due to the new ECU in the 2014's and better programming. When the 2014 6.2's are available I will test drive and if it shifts as smoothly as the 5.3 I am buying one for certain. As good as the tranny shifts on the 2014 the motor was not even close to the torque of my 6.2 down low. I had to relearn the pedal in my 6.2 when I got it back with more torque immediately available. The 2014 5.3 however did not flatten out like my 6.2 does above 5k rpm.

NKPPhil

Wow, man, thanks for the very thorough report - and congrats on the warranty repair!

gonzo 6.2

iTrader: (8)

could it be clutch pack not "basket"? could that be a forward drum not 1-4? im just stabbing in the dark here.sounds to be like a true factory.sounds to be like a true factory defect.

Glad you got it fixed and warrenty was your friend

NemesisC5

I feel very fortunate to have everything covered under warranty. I forgot to mention that on the second R&R the repair tech replaced 1st through 4th gear clutches just to make sure he gave it everything possible not to have to do it over.

NemesisC5

Thanks and you could be right Gonzo, I was stabbing in dark as well since my memory is shot to hell. I do believe it was a flawed casting just waiting to break.

gonzo 6.2

iTrader: (8)

the tech missed it the first time,had he air checked it he would have caught it.