Changing the transaxle fluid in a 944 is a pretty simple job. It’s one that is worth doing if you want this old car to last as long as possible, as for a change interval, I would change it every 50k or every two years, whichever comes first.
There are a couple of things that you will need in order to accomplish the goal of putting new fluid in the transaxle.
You will need new fluid! I used the Royal Purple Max Gear 75W-90 Gear Oil. I found this information in this article on Clark’s Garage. I purchased 3 quarts.
You will also need a way to get the oil into the transaxle. Since it is mounted under the car this can prove quite difficult. At first I tried a long tube and cut the tip off of the Gear oil Container. This did not work so well and would have taken forever. I then found that I could use the fluid pump that I use for the GMC Envoy Transfer case. This worked much better and would recommend one of these.
Something else that is required is a 17mm hex key / wrench / socket. I did not have one of these and had to go out and purchase one.
A breaker bar is nice to break loose the fill and drain plugs.
And a catch can of some sorts to catch the old oil.
Of course, you wouldn’t be doing this if you didn’t have some skill already so I’m assuming that you have a jack and jack stands. If you don’t, you will need those as well!
The procedure for accomplishing this task is very straight forward.
First you will want to jack up the car. I had mine up on jack stands already since I was doing a brake job on it but you will need to lift the rear of the car off the ground and support it properly.
Then you will want to loosen the top fill plug. Make sure you can get this one out before taking out the drain plug. Nothing worse than draining all the fluid and not being able to put it back!
Once you remove the fill plug, position the catch can underneath the drain plug and remove the drain plug from the car.
Once all the fluid is drained from the transaxle, replace the drain plug.
Now the fun begins! This is actually pretty easy if you purchased the fluid pump. Attach the fluid pump to the top of the gear oil container and route the hose to the fill plug. Pump the fluid into the transaxle. This will be slightly difficult depending on the length of hose that you have connected to the fluid pump because you will need to flip the Oil container upside down in order to get most of it in. When I drained all three, I put the remaining fluid all into one container and did it again to fill it to the top.
Replace the fill plug, put the car back on the ground, and you are done!