Found my problem to be a metal fluid pipe inside broke off and it is loosing pressure for the forward gears, and the trans cooler pipes were leaking.
Replaced the parts and working smoothly now.

 

Any indication of why the piping broke ? Seems like a rare failure, not one I've heard of before.

 

My in-laws are having this exact same issue right now. I am checking everything theirs is a 2010 LT flex fuel and it actually did it going down the road. Guess I'm going to have to tell them more than likely it's a tranny replacement.

 

Not necessarily a transmission replacement, it could be just the pipe cracked at the weld, drop the fluid pan and filter, the pipes are above that.
are there any codes? Like P0976 or P0977? Solenoids will set a code.

 

We have heard of the broken pipe before, not very often. That should cause a P0961.
NOT a cause for new transmission.
If you are a person that thinks changing ATF is "regular maintenance" it might be happen when replacing the filter.

 

Which "exact same" issue is the car having? This thread has 3 or 4 different people saying that had the same issue; but actually were not the same.

 

These threads get very convoluted very quickly. Best to start a new thread on your problem.

 

Their issue is the car revs and runs in reverse just fine. It is drive or I should say any forward gear is not work. I can rev it up or try to easy into it and it has nothing other than the engine reving. No code are popping up except an exhaust the flex pipe after the header and the before the second o2 sensor. That flex pipe is cracked and you can smell the exhaust in the car. Told them they need to get it fix. Now it's sitting in my yard cause I was nice to bring it here cause it was closer to my house and I took them home.

But the issue that is the biggest is the no forward motion no matter what is done other than literally pushing it.

 

See post # 21


This pipe assembly, it’s above the fluid pan and filter, if there’s a leak in these pipes the car won’t move.

 

A video of changing the pipes