I’m a fan of the round number maintenance interval. The 50k maintenance for me consists of a Radiator Flush and Fill, Transfer Case Fluid Change, and the Transmission Fluid Change. This article is going to show you how I do the Transmission Fluid and Filter change on a 2007 GMC Envoy.
You will need to determine which transmission filter kit to get. There are two types, one for a deep pan and one for a shallow pan. The way to tell is the shape of the pan. The deep pan will have a lip on it and the shallow pan will not, as explained in this article.
You will also need 5 quarts of ATF Fluid. I used Full synthetic Valvoline this time since that is what AutoZone had on the shelf and it met the Dexron IV specification that is required.
A funnel with a narrow spout would also be useful for filling up the pan when you are done.
First, get the truck supported on some jack stands so that you can get under it and perform this operation.
Put a piece of cardboard down on the driveway, or wherever you are, to soak up any of the fluid that spills and to try and keep the area as clean as possible. I have learned this lesson the hard way and my driveway has paid the price!
You will need to loosen all of the 13mm bolts that are holding the pan onto the bottom of the transmission.
Loosen one corner more than the others to allow the fluid to start to pour out of the pan. Be smart about this and loosen one of the back corners if you have the front of the vehicle lifted, if for some reason you lifted the back, do one of the front corners. This will allow some of the fluid to drain out and make it a little easier to drop the pan.
Once the fluid has stopped draining, pull a little on the corner and get some more fluid out. Don’t bend the pan or anything; you just don’t want the fluid to be right at the top when you finally drop it.
Remove all the bolts except for a few, do it how you want but I would recommend leaving 3 bolts in the corners. When all the bolts are removed, except the few you left, you will need to hold the pan with one hand and remove the bolts with the other. This is why there are no pictures of this. If you don’t do it this way you will have transmission fluid all over the place since there is still some in the pan.
Once you have the pan down, you will need to drain the remaining fluid into your catch can. Then you will see a magnet in the bottom of the pan that catches all the metal shavings after years of use. You will want to clean the magnet and the bottom of the pan till there is no fluid or metal remaining. You will also want to clean around the mating surface for the transmission pan so that there is a clean surface for the new gasket.
Drain This Fluid
Magnet to Catch Shavings
Pull down the filter, this should pull straight down. Be careful, there will be some fluid left in the filter. Put the old filter in the drain pan or turn it and drain the fluid into the catch can.
I just laid it on a piece of cardboard that I had put down so that it would not leak on the driveway. I found out later that there was still fluid in it…..
There is a screen in the hole that the filter comes out of; if you feel so inclined you can replace this as well. It may be a little difficult to remove, but it should come in the kit.
Install the new filter; it should just slide right into the hole the screen was in.
Align the new gasket on the transmission filter. Choose four bolts on the corners to start to install the pan. Once you have the bolts started the pan should stay up and you can install the rest of the bolts. Tighten them all up, I did not even look up the torque specs but just tightened them similar to how hard they were to break. You don’t want them too tight because the heads will snap off.
Put the truck back down on the ground and fill up the Transmission with fluid. There are marks on the dip stick that will show you the hot fill level, I filled it till it was at the bottom of the dip stick and then started the truck. Once it was up to temperature, I shifted into drive and reverse and rechecked. At this point I filled the pan till the fluid was in the marks.