Try the transmission flush
It worked for me. I'm 1500-2000 miles on it, haven't felt it once since.
Make sure it's a full flush, and that you do it at a toyota dealership (not all of them will do a full flush either, most of them will just do a fluid change)
So I wanted to follow up. I took my 2010 Trail to the dealer. They confirmed the shudder between 30-45 (and 40-50 as well) as the torque converter.
He was a straight shooter, said that they don't do trans flushes there, but they do at another Toyota Dealer.
I took it to that Dealer, did the...
So I just called to ask the dealer -- apparently the "confirmation" was them seeing there was a TSB out from Toyota with this described issue, which calls for replacing the torque converter. Then the previous owner declined the service.
So it seems it's still a mystery. I'm going to try...
Just wanted to say I have the exact same issues as described here JAXJeremy. Just took the last half hour to read this entire thread.
I have a 2010 Trail edition. Have the same exact rumble as you, the same conditions bring it on.
Had it for 3 months, 75k miles on it, I've put on 3k...