Transmission Dipstick tubes
Before giving the below advice, Make damn sure the Stick & Tube are the correct part numbers, Low fluid level is the #1 killer of auto transmissions!
You can remove the stop, In fact...In '05 GM stopped using them & changed the design of the pan with a "Step" where the Stick goes through for more accurate ATF level readings (Reduces slosh) 24240207 is the part# & goes for about $13 at the dealer.
Here is a pic of the pan on my Camaro, '05/'06 GTO uses the same pan
Here's a pic with the dipstick inserted. I know I have the correct matching dipstick and tube, on the stick itself it says to use the deep pan.
Looking at the pic, my set up would work if I didn't have that notch in the pan. I've seen some pans that were deep and didn't have that. Maybe that's what I need? The stick would def work with that type of pan
I'm going to do some research, I do have an option of having a custom length dipstick made if I went that route. Just trying to get the best option
The pic could be misleading, the dipstick is almost even with the filter, just a hair above. It's the angle I took it, and it doesn't go below that

But, I know for a fact GTO's used that same pan you have in '05 & '06.
Just make sure the stick is marked correctly!, Compare it to the old set-up you had....(How deep in the trans the Cold & Hot marks are).
Here's the dipstick end against my old dipstick. GTO dipstick is on the bottom and the old one on top
The marks for the GTO is on the very end, which seems like it would be for a deep pan without the notch


Here's how far the old dipstick stuck out of the tube
I guess my only other option is to measure the dipstick and get the member here on this site to make me one custom fit.







