Transmission issue

So I had my 2007 tundra transmission rebuilt, but ever since truck shakes between 30-40 mph. I’ve taken the truck back 3 times already because it still has warranty. And all 3 times after a week the issue comes back. But I just recently noticed that when the truck is in S mode, no more shakes. Any ideas of what it could be so I can tell them? (Torque converter) maybe.
I’m going to take it back one more time, and if the same issue continues going to cut my losses and go somewhere else. Never going to use these guys again.

 

Easy stuff first. Do you know conclusively, for sure and with 101% certainty what make of transmission fluid they used when they refilled it?

 

I can almost guarantee they didn't do the proper fluid level procedure either

 

No i don’t, but i will ask when I drop it off. Or at least mention it

 

bad shift solenoid?