Bavarian39

Maybe this might be helpful to some of you who were thinking about changing the transmission fluid in your GS without going to the dealer. I did this just as regular maintenance like I do with all my other cars with the so called "LifeTime Fluid".....
Keep in mind that this is a AWD model and the procedure for RWD might be slightly different.
I did this on a lift so doing it on jack stands might be more challenging.

First we have the FILL PLUG that we need to crack open before we do anything else. It's located on the driver side next to the shifter linkage.





The plug requires a SHORT 24MM socket. You can see how little room there is between the plug and the front driveshaft.



Next we see the drain plug on the right and the exhaust hangers on the left that we have to remove the bolts from for clearance when taking the pan off.



I chose to measure out how much fluid I drained and fill it with exactly how much I drained out. So I drained everything into plastic jugs to measure. At 70,000 miles the fluid was dark but not black. Also didn't smell burnt or anything. If you just drain without removing the pan it will be about 3.5 quarts of fluid. If you do remove the pan and filter it will be about 4.8 quarts. There is a surprising amount of fluid that remains in the filter.





Here is a snapshot of the pan and filter removed. The filter is held on by a few 10mm bolts that are easy to spot. Keep in mind that you have to use a pry bar to move the exhaust hangers down that you can see on the left or else you will not have room to remove the pan. I had to pry mine down because the bolts on the actual exhaust flange were rusted in place.



Here is where things were interesting. According to the Lexus parts rep, the filters on the AWD cars are a reusable metal mesh design that can be cleaned out with carb & brake cleaner. The RWD cars have a regular paper mesh filter that must be replaced. The AWD filter costs $90 if you choose to replace it, the pan gasket was $35. I chose to let mine soak in brake cleaner as it looked very clean inside. I then blew it out with compressed air and let it sit out in the sun for an hour to dry it completely

drgrant

Nice... did you have any plans to get rid of the other crap in the transmission? (there's usually more fluid lurking inside that doesn't drain).... although 4.8 quarts is a lot so that's surely better than not doing it!

-Mike

Bavarian39

I plan on driving about 5000 miles then doing a drain and fill. That should replace about 8.5 quarts total. Luckily a simple drain and fill is easy on these cars, can't say the same about all the BMW's I had to do this on...

UDel

Thank you for the DIY. I don't buy into that "lifetime" trans fluid either, I will do drain and flushes around 70K miles. I will just do the straight drain and flush though and not take off the pan/filter(more things I might screw up/break. I guess it will just take about one more drain and flush to do it without removing the pan.

NYLiqPlat

Bavarian39

I've looked at two different 4GS and both were missing that cover. So I'm assuming our cars didn't come with them?

praetor

The 4GS does not have a cover to access the fill hole.

mdr2001

Great Thread Bavarian39,

I did a drain and fill today on my 2013 RWD GS350 and it does have the cover. The cover has 4 10mm bolts and 2 nylon fasteners on the back that attach to threaded posts on the frame. If needed, I can take a photo or look on the part for information. I left the cover off, as I plan to do a few more drain and fills over the next few weeks. As a note, I removed 2.25 quarts with the car level(no pan drop). My car had 60K miles and the fluid was brown, but in good condition otherwise.

Bavarian39

Thanks for the info! I'm wondering if its a RWD vs AWD thing with having that cover, its also good to know that the RWD will drain out 2.25 quarts vs the 3.5 in the AWD.

mdr2001

That would be my guess - I know your write-up is for AWD, but the steps and pictures were pretty exact to my procedure. I had to remove a cover that was over the fill bolt location, but aside from those two items, it was the same process.

I did look in the 2013 manual and noticed 8.3 quart total capacity for RWD vs.10.6 quart for AWD, so the additional fluid you drained seems in line with the capacity increase.

bclexus

FYI-

Your 1st Drain & Fill removed 27.11% of the old fluid with 72.89% of the old fluid remaining. The following is a list of the 'removed' old fluid and 'remaining' old fluid as you do successive Drain & Fills as the new fluid becomes mixed with the remaining old fluid. It is recommended that you drive ~100 miles or more between Drain & Fills to thoroughly mix the old and new fluid, and for the new fluid to help gradually flush varnish. Doing Drain & Fills will be more time consuming and cost more in terms of fluid needed compared to dropping the pan and doing it all at one time, but adding new fluid gradually a small amount each time has its benefits. Oftentimes replacing transmission fluid all at one time can cause problems.

It is recommended that you bring the old fluid remaining down to around 20% if not lower, so you should do at least 5 Drain & Fills if not more.

1st: 27.11% removed with 72.89% remaining
2nd: 46.87% removed with 52.13% remaining
3rd: 61.27% removed with 38.73% remaining
4th: 71.77% removed with 28.23% remaining
5th: 79.42% removed with 20.58% remaining
6th: 85.00% removed with 15.00% remaining
7th: 89.07% removed with 10.93% remaining
8th: 92.03% removed with 7.97% remaining
9th: 94.19% removed with 5.81% remaining
10th: 95.77% removed with 4.23% remaining

jordanhigg

Thank you for this. I just bought a 2015 gs350 with 55k and plan to do a drain fill.

for beginners like me- for a drain fill you just pulled the drain plug and then added more fluid in the fill hope with the garden sprayer/hose. I've seen hand pumps at Autozone for pretty cheap, i will probably go that route

mdr2001

Hey bclexus,

I appreciate the comments and was also closely following the other thread on this topic with your spreadsheet (thank you for that handy item). I was planning on doing about 5 to see how the fluid looked by then - hopefully red or slight brown(ish). If I am not happy with the fluid color on drain 5 I will probably add 2 more to the mix. The commentary and review done on the board has been a great help.

mdr2001

As many have mentioned, I would remove the fill bolt BEFORE you remove the drain bolt to ensure you can refill the transmission pan once you drain it. Other than that I recommend this very simple video for creating a fluid pump on the cheap.

youtube.com/watch?v=VbNhswhnvuA

jordanhigg

thank you again for the detailed information