[How-to] 2012 Sonata Transmission Fluid Change
There isn't to much online regarding tutorials for DIY maintenance so I figured I will write them as I go.
I have 67,000 on my Sonata. I have been noticing intermittent problems shifting up and down while driving. It didn't happen during specific times (sometimes when the motor was cold and others when it was warm). I figured I'll start easy with new tranny fluid and go from there. After the new fluid and a can of Transtune, it has never shifted better.
Castrol MaxImport - SPIII
Transtune - 1 pint
Tools Need: 10mm socket/wrench, philips screwdriver, 15/16 wrench, 3/8 drive socket wrench, filling tube (small diameter)
1.) Jack up the car. Ideally you want to put the whole car up sitting evenly on jack stands. I used a lift so it was easy.
2.) Take off the splash guard. This is attached with multiple 10mm bolts and philips head screws. Have fun with this, there are a lot.
3.) Drain the tranny and let it drip until it completely stops. The drain plug is 15/16 and is located directly on on the bottom of the tranny. Once you start draining it make sure to clean off the magnet as there will be shavings attached to it. Once it has stopped dripping out, put the drain plug back in and torque it down (Not too tight)
4.) Grab the 3/8 drive socket wrench and find the fill cap on the front side of the trans. It will be black with 2 knobs on the edges. The middle of the fill cap is where you will place the 3/8 drive and loosen it up. Take this off.
5.) Now find your filler tube run it from the top of the car down to the opening and stick it in the trans (Won't go to far in). Start filling the line from the top, this will take some time. I used a small funnel which helped speed up the process. I put the transtune in at this time as well.
6.) Once it starts dripping from the fill hole, its full... for now. You want to get in the car and turn it on. Let it run up to operating temperature. The fluid needs to be between 122-140 degrees. Once it is at running temp, shift through the gears multiple times and sit in each gear for 30 seconds.
7.) Go back to the filler tube and start putting more fluid in. Mine took another quart after shifting through the gears. Once it starts dripping again pull it out and let it drip out until it is dripping very little (almost stopped). Put the filler cap back on and tighten it down with the 3/8 drive wrench.
8.) Done, dunzo, finished, complete.
**If you want to ensure it is filled correctly, drive around the city making sure you shift between 1st and 6th gear multiple times. Jack it up again, evenly, and open the fill cap. You can see if it will take anymore. If it is still dripping very slightly then you have the correct amount of fluid.
Current: 2012 Sonata GLS - 5% tint around back - 35% on front windows. LED interior lighting
Past: Built 1993 Mazda MX3 - 330hp
1998 E36 BMW