How-to: ATF Fluid Flush Without Pan Drop
Hey all, I have a 2009 Pontiac G5 with about 150k kms (93k miles) and thought I'd try my hand at an automatic transmission fluid flush. Everywhere online suggested dropping the pan, replacing the filter, gasket, etc. I found a different (and way easier) way of going about it.
Firstly, go underneath the car while the engine and transmission are cool, and undo the transmission fill check bolt. If you look at a diagram of the 4T45 online, you'll notice that the fill cap under the hood is on the opposite side of the transmission than the level check. The rest is quite simple. I just added 4L of DEXRON-VI ATF fluid under the hood, which caused a lot of old fluid to flow out of the fill check bolt and into my catch. Now, the car drives incredibly; I've never felt it shift so smooth in my years owning it.
Now to be clear, this isn't going to get all of the ATF fluid out (it's not a true flush). However, I think doing this process with 1-2L (1-2qt) of fluid every year will keep the transmission clean enough to avoid any issues, and extend its life. Doing a pan drop is way too difficult for most people, and this way will improve your transmission's life and drivability without much work involved.
Let me know what you guys think about this process. It worked for me, so I just thought I'd share.