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9T50 transmission fluid drain/refill tips

15K views 30 replies 6 participants last post by  PoManMali  
#1 ·
Hi everyone,

I drained/refilled the 9 speed AT in my 2017 Malibu Premier recently. There's a lot of digital ink spilled on the 6 speed in the forum but not much about the 9 speed. Here's my experiences with 2 drain/refills on my Malibu and the 1st drain/refill on my wife's 2020 Terrain, which also has the 9T50

- The service manual says draining will result in 5.3-6.3 qts of fluid. During the 1st drain, I got 5.8 qts out, right in the middle of the range. BUT, on the 2nd drain/fill (I did two drain/fills to maximize the new fluid in the AT), I drained 6.8 qts. I was perplexed but this (and bit freaked out) but I did indeed drain 6.8 qts on the 2nd try. In my wife's Terrain, i got 6.3 qts.

My suggestion is if you try to change it yourself, assume you'll need 7 qts.

- With the extensive help (and patience) from Campb292 during the process, we both guessed as to why the 2nd drain was a quart more the 1st time: different drain period allowed. On the first drain/refill, when the bulk of the fluid was drained and just a small stream was left (about 10 minutes of drain time), I replaced the plug. On the 2nd drain, I let the car drain for over 2 hrs. During the last 1.5 hrs., that small dribble/stream netted 1/2 qt. alone. I did the same with the Terrain, hence the larger amount of drained fluid.

- I suggest for the last drain replacing the drain plug with a new one. It's not that the plug is damaged but the factory plug has yellow material in the threads to prevent any weeping. It is NOT threadlock either. After one removal that yellow stuff is gone. Amazon sells the OE plug for around $4.29, the listing is here:


Also, the torque spec for the plug is 12 ft-lbs; it's pretty light torque and the plug is tapered (making it easy to over-torque). Take it easy with reistalling the plug; when I felt some resistance, I stopped and every day or two I'd check for plug leaks or weeping. I had some weeping after the 1st drain/fill, an 1/8th turn of the plug fixed it. I haven't seen any weeping with the new drain plug since I installed it 10 days ago.

- Regarding the 6.8 qt. 2nd fill: I was extremely concerned that I overfilled the transmission even though I checked what I drained 4 times and came up with the same amount each time I re-measured. The shop manual procedure to check the fluid level isn't shade-tree mechanic friendly so I bit the bullet and let the dealership check. The dealership tech said the fluid level was spot on.

- It's not necessary but I used the full-synthetic version of ACDelco's Dexron VI fluid. It's available from Amazon, price difference isn't that much more than the std. Dexron VI. Rock Auto though beats Amazon's price, in particular if you're ordering for 2 drain/fills then it's worth getting it from Rock Auto instead of Amazon. In my neck of the woods (central North Carolina), no auto parts store carried ACDelco except for dealerships. The only upside to getting it from Amazon is if you over-buy, they'll accept returns for the unopened containers.

That's about it, overall the drain/refill procedure is the same as with the 6 speed auto but there are a few differences to know before you DIY.
 
#2 ·
Talk about perfect timing, tomorrow I'm going to do the first drain and refill on my 2017 Malibu Premier. Thanks for posting your experience with the 9 speed in the Premier!!! I bought 2 gallons of the Valvoline Dexron-VI since I'm already using it in my TBucket (Avatar). I have 4 quarts on the shelf, so that gives me 12 quarts.

It seems the amount one gets during the drain period would also depend on how long the car has set before pulling the drain plug. If the car sits for a week, then you pull the drain plug .... well you could expect a larger amount of fluid.
 
#3 ·
I waited at least 4 days in each case, longer the 1st time (6 days) compared to the 2nd time (4 days). I'd say after a day it doesn't really matter, whatever drained back won't increase. What did matter was the time to let it drain, that slooow stream after a few hours does add up. Where the extra quart came come I do not know.

Glad my experience can help out. I sure have gotten a lot of good advice, from Campb in particular.
 
#5 ·
Torque convertor holds a lot of fluid, the longer it sits the more will drain out of it over time. Total rebuild spec. is about 11 qts. I think. Full rebuild gets every drop out.
That's why we say measure what comes out at the time of draining and put that amount back in to be as precise as possible.
 
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#6 ·
Torque convertor holds a lot of fluid, the longer it sits the more will drain out of it over time. Total rebuild spec. is about 11 qts. I think. Full rebuild gets every drop out.
That's why we say measure what comes out at the time of draining and put that amount back in to be as precise as possible.
I did measure it, 4 times. I got out that much since the SI (Service Information, aka shop manual) says 5.3-6.3 qts and I got 6.8 qts. so I assumed I was imagining things, especially since a few weeks before I got 5.8 qts out.

Granted, most wouldn't let the vehicle sit for 2+ hrs. dribbling out fluid. Apparently I did get out more than the SI says since the dealership verified filled it properly.

So out of curiosity, if I let it sit, say for days (weeks even), would the torque converter be fully drained? I thought it just held some fluid and wouldn't let it go unless it's taken apart.

Bottom line, have at least 7 qts. on hand to refill the 9T50 if you attempt this service and don't be surprised if you get more than the SI's listed amount either. I'd also suggest using a new drain plug after the last drain/fill too.
 
#12 ·
The explicit procedure to check the fluid. I highlighted the important tidbits. This is why I had the dealership check the level:

1. Drive the vehicle for 10 min to allow the transmission fluid to warm up. The transmission fluid level must be checked when the transmission fluid temperature (TFT) is 85– 95°C (185–203°F). Driving for 10 to 15 minutes will put the transmission fluid temperature in the required range. The transmission fluid temperature should be checked with a SCAN tool (I found it takes about 20 min. to get the ATF to the right temp).

2. Keep the engine running and let it idle.

3.Depress the brake pedal and move the shift lever through each gear range, pausing for about 3 seconds in each range. Then move the shift lever back to PARK (P).

4. Allow the engine to idle 500–800 rpm for at least 3 minutes to allow any fluid foaming to dissipate and the fluid level to stabilize.

5. Release the brake pedal.

6. Keep the engine running and observe the transmission fluid temperature (TFT) using the SCAN tool.

Caution: The transmission fluid level must be checked when the transmission fluid temperature (TFT) is at 85–95°C (185–203°F). If the TFT is not at this temperature, operate the vehicle or allow the fluid to cool as required. Setting the fluid level with a TFT outside this temperature will result in either an under or over-filled transmission. TFT 95°C under-filled, TFT 85°C over-filled. An under-filled transmission will cause premature component wear or damage. An over-filled transmission will cause fluid to discharge out the vent tube, fluid foaming, or pump cavitation.

7. Raise the vehicle on a hoist. The vehicle must be level, with the engine running and the shift lever in the PARK range.

8. Remove the driver-side front wheel. While the vehicle is idling, remove the oil level set plug (1). Allow any fluid to drain:
• If the fluid is flowing as a steady stream, wait until the fluid begins to drip.
• If no fluid comes out, add fluid until fluid drips out.

9. Record fluid level; overfilled, under-filled, correct on repair order and how much was needed to fill or came out:
• If fluid is overfilled, set correct level and retest.
• If fluid is under-filled, inspect for external leaks.

Refer to Fluid Leak Diagnosis in SI.
 
#14 ·
I did the same, drain/measure (carefully). 1st drain resulted in 5.8 qts, right in the middle of the shop manual's drain range. What I got out of the car was in spec so I was pretty sure I was doing everything right. The manual says 5.3-6.3 qts is how much the 9T50 will drain.

I drained/filled the ATF on my wife's 2020 Terrain (uses the same 9T50) a couple of weeks later, I got the max amount, 6.3 qts. The Terrain has stop/start so I thought the 1/2 qt more was due to the transmission's accumulator used as part of the stop/start system. Still, the drained amount was in the SI's range.

When I did mine for the 2nd drain and got 6.8 qts. I was concerned, especially since two weeks before for the first drain I got 1 qt. less. I measured 4 times but still wasn't convinced until I got the dealer to check it for me.

That's the main reason I posted the above, in case anyone ran into the same issue.
 
#16 ·
Well one thing lead to another, but I finally got back to the Malibu.

After letting the car set overnight I drained the trans and got close o 5.5 quarts of fluid. Since we didn't need the car I put the drain plug back in and let it set again overnight.

The total fluid drained from the trains was 5.5 quarts.

I put back just a smidge over 5.5 quarts to make up for what would be left in the drain pan, funnel and hose.

Image
 
#17 ·
Interesting Indy, I wonder why I pulled so much from my car in much less time. Granted it, was the 2nd drain that I got the much greater amount.

I'm doing the 2nd drain/refill of my wife's Terrain either tomorrow or Tuesday, I wonder if it'll be the same amount as the first drain.
 
#19 ·
Overnight drain will let more out than a quick drain. Overhaul capacity is around 10 qts. so some will drain back out of the torque convertor and what seeps out of the valve body when sitting a long time.
Main thing is no matter how long you let it drain is putting back in the same amount.
 
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#20 ·
That fluid looks nasty. Any plans to do repeat drain/fills?

I know I've been itching to get a 3rd drain/fill done on the 6T40 on my 8th gen. Did it's first a few weeks ago @ 81K miles. Fluid was ugly. I used Castrol Transmax universal ATF/CVT fluid.
 
#21 ·
Do not use universal fluids period. Use only a dedicated Dexron VI fluid only. Dex VI may have a Ford LV approval also on the bottle but that's OK as some Fords use Dex VI.
Meets and is are two different things.
 
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#22 ·
Do not use universal fluids period. Use only a dedicated Dexron VI fluid only. Dex VI may have a Ford LV approval also on the bottle but that's OK as some Fords use Dex VI.
Meets and is are two different things.
Just curious if you've seen failures on the 9T50 or 6T40 where "suitable for use" fluids were used.

I've been using maxlife or the above mentioned Castrol Transmax for years in various domestic and import ATs and CVTs for years without issue.

If I was paying a shop to do the job, I would expect them to use OEM fluids.
 
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#25 ·
My daughter has put about 500 miles on my 2016 8th gen after I've run 2 gallons of Castrol Transmax though it. I'll see how it goes.

To me a lot of ATF problem posts are from people trying to fix an existing transmission problem with a fluid change. Most of the time it's not going to work.
 
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#26 ·
Only factory approved fluids in transmissions. One example of a different fluid is in GM 8 speed trans. in Camaro's and trucks. Torque convertor shudder appears in some units. GM instructed dealers to replace fluid in them with M1 LV HP blue label fluid. It stopped the shudder. I seems regular Dex VI is hydroscopic and was causing a shudder when convertor locked and unlocked. It is Dexron approved for use in high performance transmissions hence the HP designation.
I just did a fluid change in my '20 Traverse 9 speed with it since it's a more robust Dexron fluid that is OEM in Corvettes.
 
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#28 ·
Now you know why the severe schedule says every 45k miles.
 
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#31 ·
Everyone's experiences and opinions are going to vary. That said, I did another drain/fill with "suitable for Dex VI use" Castrol Transmax Universal ATF yesterday. ~15 quarts total run through this 6T40 from ~81K to ~83K miles. The fluid is getting cleaner. The transmission itself has not had any issues, just very dark ATF when we bought it last month with 81K miles on it. Still performing and acting as it should.
 
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