I don't recall the dipstick tube having anything more than a friction fit. I sure don't believe there's an e-torx involved.
If you're talking about what holds the upper part of the tube to the tub it should be nothing more than a standard 3/8-16 hex nut. The only e-torx on the transmission is one E-12 that is one of the bolts that hold the transmission to the engine.Shift linkage is off! Now the dipstick tube must be removed - from what i understand and observe, it's an e-torx bolt that must be approached from the engine compartment. Need to get the proper tool for this.