Would a smoke test be necessary on a hybrid set up? I think I already know the answer… If mods are done, or you just want to test for leaks in general, than the answer is likely ‘yes’.
I’m at review stage of selecting my next new vehicle. The 4Runner Platinum is high on my short list. I’m looking forward to owning one, likely a 2027 model. I will definitely keep this add on transmission oil cooler in mind.