Yes, he said at first that after looking at the clutches and fluid which showed no signs of wear he didn't inspect everything close enough figuring that the issue was the TCM. He said this was the first failure he has seen like mine. The repair tech was super cool and took pride in his work but sometimes like myself we make incorrect assumptions based on past history or what may seem obvious. I'm just very pleased that warranty covered what could have been a chunk of money out of my pocket.

 

Wow. Just reading up on this post. Being a GM trans builder the tech should have tested the control solenoid valve assembly (what was called TCM) on the bench. Which is just commanding solenoids on and off while supplying air pressure. If nothing wrong there tech then should have pulled trans. From what I've seen in the past in the 6L80 and 90 trans the weak points seem to be the 1-2-3-4 clutches burning up. But I love seeing new things and am impressed with the 1-2-3-4 piston cracking. Great pics and glad everything under warranty.

 

The part he was referring to was the brown plastic piece across the bottom, not the cast piece with all the mechanisms in it. The brown plastic piece has places for electrical connectors. Was I wrong in how I described it or was he wrong that it is an electronic controller? Is the TCM submerged in fluid or where is it located?

 

Yes the brown plastic piece is the control solenoid valve assembly that houses the TCM with it. It bolts to the top of the valve body. It has one pass through connector at the back of it correct? This unit houses the TCM, fluid temp sensor, pressure control solenoids, Shift solenoids, and pressure switches. They are connected by a lead frame design. No wires connecting TCM to these parts. It is all housed as one unit. There is a test plate adapter that gets bolted to the underside of it and an extension harness that goes to trans connector on harness side. This is how we test these units. We command solenoids on and off with scan tool and apply air pressure to solenoids to make sure they are holding and exhausting at the correct times.

And yes, the TCM is always submerged in fluid. And yes there are a couple other connectors going to it like input and output speed sensors. Also the PRNDL switch is connected to it at the bottom. Sorry not trying to sound like a smart *** I just like providing my customers with the correct info so they are informed and aware of they're vehicles.

I hope this clarifies a little more. Maybe I wasn't descriptive enough in my first response.

 

Great answer, I appreciate the details to help me understand its functionality. On a similar note, does the 2014 Silverado 1500 come with the same tranny/internals? The loaner I was driving while my truck was being repaired had much refined "manners". It transitioned through the gears with less delay, shifted firmer but not hard, downshifted more predictably and cleanly...overall it seemed like it was controlled either with a better "brain" or much refined programming. It would break the tires loose cleanly with what seemed like less intervention from Torque Management. I can say the same for the engine as well, overall a much improved driver experience in the 2014. Looking forward to test drive the 2014 6.2 when they arrive.

 

Yes the 2014 silverado has the same 6 speed and internals. I would bet though that there is a better program in these trucks. With all the engine changes I'm sure there have had to been some new calibrations. Also engineers have been adding preset TAP values to these trucks. Which is why right out of the gate some of these new vehicles shift Like youd want them too. There's always improvements every year and couple months sometimes. Sometimes there are new calibrations released for shift improvements and we don't even know about them until we make a repair that requires a computer reflash and then we see the updates. I haven't got to drive a new 14 silverado yet. All the pre delivery inspections get done by people at the other end of the shop.

 

I'd like to hear your opinion of the transmission performance after you have a chance to drive one. Unlike my 2011 the 2014 did not need to downshift on overpasses while in cruise at 70-75 mph. In addition the 2014's ECM was replaced with the E92 which controls the engine very smoothly, I could not feel the engine switch between V8 & V4 modes in town or on the highway.

 

Day and night difference in my opinion between my 11 6.2 stock and the 14's I've driven. It's waaay better shifting but the exact same trans.

 

If the TCM is the same I wonder if you could flash 2014 programming? I'm not so sure the aftermarket can tune the 6L80E to shift as good as the 2014 trucks...if so I'm all in for it.

 

Let us know I was thinking the same thing while reading your post .

I don't mind but it would be nice not to have to go in and out of T/H all the time . Don't get me wrong it's a great trans just the stock tuning sucks.