So our 2007 Equinox FWD has 71K miles on it and I felt it was due for a transmission fluid change.
I called the local Chevy dealership and was quoted $257 for them to remove the transmission drain plug, drain ~4 qts of fluid, and replace it with new fluid. The filter is not serviceable w/o removing the transmission. The service advisor said the fluid was expensive. I was quoted $17.94 dollars per quart (GM p/n 88900925) when I contacted the parts dept at the same dealership so he wasn't kidding.
To add insult to injury, the local Toyota dealership sells their T-IV fluid for only $6.11/qt (Toyota p/n 00279-000T4-01) which meets the JWS 3309 service specification for the 5-speed automatic Aisin AW55-51 transmission used in the 2005-2009 Equinox w/3400 engine.
DO NOT USE DEXRON-VI FLUID!!! - It is not correct for this application.
The location of the dipstick makes checking/adding fluid a big challenge. It is located just inside of the front transmission mount on the engine side. It is covered by a couple wiring harnesses so it cannot be easily seen and is impossible to remove without crawling under the car. It has a round yellow handle and is held in place with one 12mm bolt. Adding fluid requires a long flexible funnel (~2.5ft long).
After doing alot of research, I decided to attempt to do a complete transmission fluid change. It was somewhat of a challenge, but I was successful.
I was unable to take pictures, but the basic idea is covered well in this video
First, park the vehicle on a flat, level surface. Then shut off the engine and remove the transmission drain plug to drain all the fluid you can and measure what you remove. The drain plug faces the driver's side and has ~15/16" hex head. Next, remove the 12mm bolt that holds the dipstick in place and pour in the same amount of new fluid that you took out. For me it was about 3.75 qts.
Next, detach the lower
transmission cooler line from fitting on the radiator. To remove the cooling line you first need to use a small flatblade screwdriver to remove the wire clip/retainer from the fitting on the radiator then gently pull the line straight back to remove it and clamp a 3/8" (inside diameter) clear vinyl hose to it (can be had from you local Lowes for $0.33/ft). This is where the old fluid will be pumped out when the engine is started. Be sure to make a mental note of the orientation of the metal clip when you remove it as the clip will need to be installed in the same position from which it was removed.
You will need to measure the amount of fluid you remove and replace it with new fluid. It is important that you get accurate measurements, so be careful not to spill any fluid. I used an empty milk jug that I marked to keep track of how much fluid I removed. To mark the jug I filled it with water using a measuring cup and marked every 1/2 quart increment on the jug with permanent marker. This transmission is supposed to hold about 8.4 qts when it is full.
In the video the guy adds fluid while the old fluid is coming out. This won't work for the Equinox since the fluid cannot be added fast enough. I had a partner shut off the engine after each quart that I removed so I could add a quart of new fluid to replace it. I also did this because I didn't want the run the transmission out of fluid.
When you are finished, reattach the cooling line and the retaining clip. Then start the engine and cycle the transmission by moving the shifter through each gear for 3 seconds while the engine is idling and the parking brake is on. Then put it back in park, leave the engine running and check the fluid level and add as necessary.
There are two ranges on the dipstick for checking the fluid: a HOT range and a COLD range. First, go by the cold range. If the fluid level looks ok then take it for about a five mile drive and then check it when warmed up and add as necessary according to the HOT range. You must cycle through the gears with the shifter in each position for at least 3 seconds leave the engine idling in park in order for the dipstick indication to be accurate.