Sounds like the #1 check ball is wearing to the point it's no longer consistently sealing off it's seating location.

Here's a quick vid that explains further...

 

thank you, thats interesting. I wonder if the dealer would be willing to take a look at that. If this is the case why at such low mileage?

 

I had no idea you actually responded to me until @EdgecrusherXES mentioned me in his post above. Always quote my post or mention me if you'd like me to reply back. I have my notifications turned off...

Ask the dealer to take a look...it's one possible explanation - no one can diag your transmission over the net to 100% certainty but your symptoms sound like a check ball getting stuck. Can also be partially clogged and/or cracked filter (filters sometimes crack at the neck), rear sprag, pressure switch issues in the TEHCM and a host of other things as well.

Here's the thing.

If it's under warranty, the dealer has to be able to replicate the condition. I wouldn't drive it again until they do. Otherwise, you'll be 1,000 more miles down the road before you know it and overhauling it yourself or paying someone like me to do so (I'd avoid any remans except General Motors, which comes with a 3yr/100k mile warranty.

 

Get it to the dealer and have them check it.

 

Currently at the dealer. How do I convince them to open the trans and do a complete inspection. All they have done is drive it and they want to hand it back.

 

'Trans acting strange' - there is allot of that going on in our country

 

That's funny but terribly true

 

My 17 6 speed did this exact thing. At 51,000 miles, and I had changed the fluid to Amsoil at 40K. At first it was from a stop like yours, so I had to rev it and it would lightly slam into gear. about a week or 10 drives later it just stayed in neutral. It was fixed by the dealer but out of warranty, $3,300 ouch. They explained it was a stuck check ball. The repair included new upper and lower valve body, although I don't know if that was a necessary thing or they whacked me. Use Nick's info and advice and absolutely make the dealer do a full repair. Make sure all of your symptoms and complaints are in writing on the dealer paperwork, they will want to put snake oil in there to make it last the 1000 miles you have left under warranty

 

This is what baffles me as the dealer and tech get paid to fix these things under warranty. The dealer I had back home almost never turned away going deeper and fixing under warranty. Their service dept had a reputation of really top level work that they were always waiting list to get into.

 

I expect both the dealership and the mechanic to want to get paid for doing this work. GM will only pay a set amount of diagnostic time IF it is a warranty problem, and many dealers will only pay the mechanic based on that same shop-time metric. Dropping the pan means a bunch of money for new fluid that GM isn't going to pay for if there's no problem found.

 

Well. They say they cant replicate the problem. So they want me to pick it up. I need yo talk to the service manager and see if i can have them do more research. Sucks. I appreciate everyone’s comments. Ill keep you all posted.

 

Ask the service manager to drive it back and forth to work for a week....maybe you will get lucky and it will act up.

 

Rather than swap the converter under warranty, my local dealer let my shuddering 6L80 fail because it didn’t throw any codes….so I got a new warranty trans out of the deal.

I still replaced the torque converter on my own dime a year later, rather than wait for it to eventually fail.

 

Hate the way these dealers work. I picked up the truck since they couldn't replicate the problem. today the truck wont move so im having it towed back to the dealer. I did get video of it this time. Im worried it will run normal when its back at the dealer. I also wanted to buy extended warranty and they claim the policy is they wont sell it since the truck is 4 years old. I thought this was strange. Lets see what happens next. Its sad i've owned a lot of GM trucks with over 100000 miles and never a issue. This truck 59,000 miles 4 years old and the trans is done.

 

I have a video im not sure how to load it for you all to see.

 

You'll have to post your video to a site such as YouTube, then post a link to it here.

 

So the truck is back at the dealer. funny thing was when the service tech tried to drive it it had no forward gears. Monday they call me and tell me they cant replicate the problem with the tech. Now the truck drives. I asked for the service manager to call me. Since it was obviously not derivable when the service tech tried to drive it. After a few mints service tech calls me and says its under warranty. and when the tech tried to drive it, it had no forward gears. I think its some BS to almost send the truck back. Should i be expecting a extend warranty on the trans now that they have to repair it? Thanks "Nick Transmissions" I shared your video. I appreciate all the comments.

 

Yes the dealers re-build or replacement tranny should come with an independent warranty. If it's rebuilt by the dealer, only the components they replaced are covered by an extended warranty.