Transmission Fluid Change step by step

[ConeDodger]

Transmission fluid change on Buick Regal TourX


First, always be sure you can refill it before you drain it!

The port to the rear, though visible without removing anything, in my opinion, is more difficult to reach with a socket and funnel. Pushing the ECU over doesn’t help me, I still can’t get enough space.

The port under the battery requires removing a lot more stuff.

You will need: A replacement fill port, GM PN #24220728, or if you already have the port, a new fill port O-ring 24220722. Also you should have a new o-ring gasket for the bigger drain plug on bottom of the trans PN #24277807, and ideally one for the small drain port, PN #90007873.

Remove the cover from the ECU, 10mm. Lift cover off.

Push the tab at the bottom back of the ECU, and slide it up and off the tray, that is actually part of the battery tray.









Remove the battery hold down.

Remove the clip the holds the big electrical connector to the front of the plastic battery cover.






Remove the positive and negative terminals. There is a little wire to unplug from the negative terminal, don’t lose where that goes.

Remove the battery cover.

Loosen and remove the battery hold down on the bottom edge, 13mm.



Remove 3 bolts and 2 nuts that hold down the battery tray. 1 bolt is on the top. 2 are in the wells and 2 nuts are angled in the wells.

The battery holder, for me, did not come out all the way nor did it need to. But there are a number of wire looms attached to it.

On the front edge is a small wire with a push on Xmas tree.

Also on the front is a larger bundle that has a clip that can be pushed underneath with a screwdriver, this one is difficult due to the angle, its difficult to get your hand under the tray while lifting it. You may need to leave this one until last.



There is a loom at the near the vertical battery hold-down bar that is an Xmas tree push in.



Continues to part 2

 

[ConeDodger]

There is a wide clip at the back of the part that holds up the ECU that requires a screwdriver to push the top/bottom to unclip.

There is another one at the extreme back, behind the ECU, that also has push in tabs to release it.





Some other views of push in clips:







The big bundle that connects to the battery positive terminal I did not remove from the tray. This one hindered removing the tray completely.

Pull the tray up and diagonal to move it to the center of the car. You should see the transmission fill plug right next to the cable that goes to the shifter inside the cabin. You can see the big spring on the end of it, connected to be big lever.







On my car, it appears someone had already removed one of the fill plugs and replaced it with the replacement style. Either way, crack open the fill port so you know you can open it up before draining.

I then opened the inner small drain port, over a wide drain pan. It came out a very slow pace. When done, I used the 17mm allen to unscrew the larger drain plug. It can drain out an an OK rate if you do not remove it, but let the fluid drain down the threads. After many minutes, I took it out the rest of the way.





I replaced larger plug (use new o-ring) at 47 Nm, then the smaller with o-ring, at 7 Nm.

continues to part 3

 

[ConeDodger]

I got help to hold a funnel onto a very clean and completely dry (distilled water) bottle, and poured the old fluid into it. Then I let that sit for a while, and marked the level on the jug. I poured that out into my recycling container.

I filled the jug with the new trans fluid to the line. Used my funnel to pour it into the top port slowly. I used about 2.9 quarts.





Replace the filler port with new o-ring at 30 Nm.

Reinstall all the battery bolts and wiring in the reverse order.