8F35 Fluid Change Tips

[colinc755]

WARNING: Make sure you can remove both the leveling plug and the fill plug BEFORE draining the transmission!!!!

 

Recently I embarked on a task that was, in theory, simple, but in reality, was hell. That task, of course, was a routine transmission fluid change on the 8F35 transmission (found in 2019+ edges with the 2.0). As it turns out, Ford has made changing the transmission fluid on this car incredibly difficult, but there are some useful things I learned along the way that should hopefully make it easier for any DIY'ers wanting to take this on.

 

The 8F35 fluid change procedure is pretty much identical to the 6F35 procedure found in the '15-'18 2nd gens. This means that there is no dipstick, fluid level is checked by a leveling plug in the left front wheel well. Sounds simple enough, many cars do this, so what's the big deal? Well, Ford decided to absolutely bury the pressure ring fit fill plug underneath a ton of immovable objects (this is unlike the 6f35 which actually had a very easy-to-access fill plug).

 

Like the shop manual says, the airbox must be removed. This is simple enough but because of the amount of "Christmas tree" wiring harness holders, you will likely be cutting a few zip ties. I would actually recommend cutting them because the wiring harness they hold is actually not in danger of hitting anything. Once the airbox is removed you must first find the cap under all the crap they buried it under. Be careful not to damage the MAF when moving the airbox away from the car.

 

Once that is done, filling the transmission is not as simple as removing the top plastic cap. You must also remove the funnel that the cap rests in because Ford placed a piece of plastic in between the cap and the funnel, blocking any fluid that tries to enter. To remove this you must get a pair of needle-nose pliers and pinch in the snap ring and pull up on the assembly. This window that the pliers can fit in is incredibly tiny and removing this funnel will take a lot of patience. Once the funnel is removed, keep track of that plastic piece that sits inside it. You can now fill the transmission with fluid, I would recommend trying to match what came out and add .25qts-.5qts to it (this is because if you pour too little fluid you can't add anymore without removing everything you just removed).

 

Once all the fluid has been added, you must now reinstall the funnel for the cap. This is where the tip comes into play. Because of the amount of stuff in the way, it is pretty impossible to squeeze the snap ring in and also push the funnel down in the right spot at the right time. What I ended up doing to solve this was to squeeze the snap ring in and have a partner wrap a zip-tie around the teeth (of the snap ring) that the pliers were grabbing onto. If you tweak this and get it tight enough, the zip-tie should hold it at maximum tension. I had to use a large zip-tie so that it did not snap. With tension held, the funnel can be easily slipped on and the rest can be reinstalled.

 

You must now hook up a scan tool and go for a test drive to get the fluid hot enough to level it (usually a 20-minute test drive). Just another side note, the leveling plug is torqued an insane amount from the factory so be prepared to break out the breaker bar and extensions to snap it loose. When you get back from this test drive, pray that at least some fluid trickles out of the level, or it's back to step 1. You can actually do an initial level before the test drive by starting the car and running it through all the gears and then checking the level plug. Just make sure the car is still idling when checking the leveling plug. That initial check is only supposed to be for an overhauled transmission, but it could save driving around with too little fluid for half an hour. 

 

Anyway, sorry that seemed like a bit of a rant. There is just a lot of unneeded complexity to this routine maintenance item. It seems Ford has made drain and fills extremely difficult, maybe they'd rather people get their transmissions flushed by machines at dealers than to have the fluid changed by regulars at home. To anyone that gives this a shot, good luck. I was originally going to make all of this a video but was too tired and annoyed by the end of all of it. If these instructions aren't clear enough, I may still do that. I will attach the factory ford guide, it makes the job seem WAY easier than it actually is. 

Transmission Fluid Drain and Refill.pdf

Edited November 9, 2021 by colinc755

[WWWPerfA_ZN0W]

good info, nice writeup.

[krzyh7]

Hello

 

This is my very first post here so would like to welcome the community:)

 

And the question is - how much fluid do I need for the change procedure?

[colinc755]

1 hour ago, krzyh7 said:

Hello

 

This is my very first post here so would like to welcome the community:)

 

And the question is - how much fluid do I need for the change procedure?

That’s tough, I remember it taking like 5.5-6qts when it was all said and done but I like to have a margin for error so I always recommend buying 8 quarts for it. It’s around 5 dollars a quart if I remember right.

[krzyh7]

ok, thanks a lot

[kruzr1]

Thought I would post this here as a comparison/reference. 

I recently did a fluid change on my 2019 Edge ST with the 8F57 transmission. I did not encounter any problems that colinc755 had with his 8F35 transmission. I did remove the airbox to get easier access to the fill/vent plug but there was nothing else attached to it, it came straight out. On a side note, I could've probably just removed one of the intake hoses to gain access to the fill plug. The fill plug itself was easily accessible and was held on by a squeeze clamp and came off easy.  Neither the drain plug or level plug were difficult to remove, used a 3/8 drive ratchet with a 3/8 hex socket to remove the level plug. I did remove the tire and set the ride height with a jack and stand to get access to the level plug but turns out it can be reached by turning the wheel out. The amount of fluid that came out was 4 quarts and 12 ounces. My work shop manual says this:

2. Remove the transmission vent cap and fill with transmission fluid.
   1. Transmission overhaul (includes main control and torque converter drain)
      Volume : 6.34  qt ( 6  L)
   2. Main control overhaul or replace (with out transmission overhaul)
      Material : Motorcraft® MERCON® ULV Automatic Transmission Fluid / XT-12-QULV (WSS-M2C949-A) (MERCON® ULV)
      Volume : 5.28  qt ( 5  L)

I refilled with 4 quarts and 16 ounces. The hardest part was probably trying to get the transmission up to operating temp. I drove around for at least 20 minutes and also used sport mode to help. When I did get to the leveling procedure, I had some fluid seep out for a bit and then slowed to a drip and I reinstalled the level plug. I have been monitoring fluid temps off and on since without any issues.  I don't have a lot of miles on my ST but I believe in being proactive, and as has been said before "no fluid lasts forever". I've also replaced fluid in my PTU and RDU already.

[colinc755]

28 minutes ago, kruzr1 said:

Thought I would post this here as a comparison/reference. 

I recently did a fluid change on my 2019 Edge ST with the 8F57 transmission. I did not encounter any problems that colinc755 had with his 8F35 transmission. I did remove the airbox to get easier access to the fill/vent plug but there was nothing else attached to it, it came straight out. On a side note, I could've probably just removed one of the intake hoses to gain access to the fill plug. The fill plug itself was easily accessible and was held on by a squeeze clamp and came off easy.  Neither the drain plug or level plug were difficult to remove, used a 3/8 drive ratchet with a 3/8 hex socket to remove the level plug. I did remove the tire and set the ride height with a jack and stand to get access to the level plug but turns out it can be reached by turning the wheel out. The amount of fluid that came out was 4 quarts and 12 ounces. My work shop manual says this:

2. Remove the transmission vent cap and fill with transmission fluid.
   1. Transmission overhaul (includes main control and torque converter drain)
      Volume : 6.34  qt ( 6  L)
   2. Main control overhaul or replace (with out transmission overhaul)
      Material : Motorcraft® MERCON® ULV Automatic Transmission Fluid / XT-12-QULV (WSS-M2C949-A) (MERCON® ULV)
      Volume : 5.28  qt ( 5  L)

I refilled with 4 quarts and 16 ounces. The hardest part was probably trying to get the transmission up to operating temp. I drove around for at least 20 minutes and also used sport mode to help. When I did get to the leveling procedure, I had some fluid seep out for a bit and then slowed to a drip and I reinstalled the level plug. I have been monitoring fluid temps off and on since without any issues.  I don't have a lot of miles on my ST but I believe in being proactive, and as has been said before "no fluid lasts forever". I've also replaced fluid in my PTU and RDU already.

That is good to hear that they left it accessible on the ST. The older 2.0's had a process very similar to yours and it was fairly easy. Good to see you noticed the wheel well accessibility for the level plug, I started thinking about that when I did it last and am going to try it next time. Removing the wheel isn't hard at all, but would be nice to skip if it wasn't absolutely needed. That fluid warmup time is also pretty crazy, I always try to tell people to really get a scan tool for it, because it takes a lot to get it up there. 

[Nooch]

 

     I have just completed changing my transmission fluid in my 2019 Ford Edge 8F35 and the Colinc755 post was dead on about this job, (a nightmare). I just joined this forum and put out a post regarding the little restrictor in the vent/fill pipe and the only reason I can come up with it's existence is for splash/spill over from the tranny. Any Ideas? I would like to remove it as it would make adding fluid a lot easier.

[akirby]

3 hours ago, Nooch said:

 

     I have just completed changing my transmission fluid in my 2019 Ford Edge 8F35 and the Colinc755 post was dead on about this job, (a nightmare). I just joined this forum and put out a post regarding the little restrictor in the vent/fill pipe and the only reason I can come up with it's existence is for splash/spill over from the tranny. Any Ideas? I would like to remove it as it would make adding fluid a lot easier.

Let the dealer do a fluid swap with the machine using the cooler lines.  Gets 97% of the old fluid and runs about $200.

[waflyboy]

On 8/18/2022 at 10:36 AM, akirby said:

Let the dealer do a fluid swap with the machine using the cooler lines.  Gets 97% of the old fluid and runs about $200.

 

I read in another thread that  @colinc755 suggested that the 8f35 doesn't do well with flushes, and recommends just doing a sump drain and fill. I'm planning to take my Edge to the dealer to change the fluid, and I know they are going to recommend flushing it. @colinc755 could you expand a little on this? (For my own knowledge and so I can have some defense for requesting a sump drain-n-fill only.

[colinc755]

1 hour ago, waflyboy said:

 

I read in another thread that  @colinc755 suggested that the 8f35 doesn't do well with flushes, and recommends just doing a sump drain and fill. I'm planning to take my Edge to the dealer to change the fluid, and I know they are going to recommend flushing it. @colinc755 could you expand a little on this? (For my own knowledge and so I can have some defense for requesting a sump drain-n-fill only.

Yeah so this whole idea generally comes from the 6F35 era. That was Ford's previous 6-speed that was found in everything and many outspoken ford techs like Ford Tech Makuloco stated that they found full flushes agitate these transmissions too much and can lead to issues. This was said to be because the transmissions are very sensitive with the clutch packs and have adaptive software that changes shift patterns based on fluid conditions. Changing too many properties of the fluid at once could cause some damage while the software catches up. The reason I apply this logic to the 8f35 is because of how similar it is to the 6f35 in that they pretty much share architecture and durability of components. A sump fill will allow for all of the preventative compounds that you need for excess ware to be refreshed, while allowing the transmission to still work under the patterns it has developed over time. Granted I don't have anything specific to prove this, and it's not nearly as much of an issue on cars that are well maintained. When I post on forums, I never know what the state of a persons vehicle is and with that mindset a sump drain is always preferable. I would hesitate to do a full flush at anything that is 60K+ and has had no preventative maintenance. For my own vehicles, I have always done sump drains and have found that my almost 70,000 mile transmissions shift better than other peoples 20,000 mile transmissions. Ultimately the best decision will come down to what you and the tech decide is the best for you specific vehicle, I am personally super cautious given the reputation ford transmissions have. Hope that helps!

[waflyboy]

Thank you for your insight! It makes sense and I really appreciate you taking the time.

 

Unfortunately, our 2019 has 62K miles and I don't think the transmission fluid has ever been serviced. We bought it 2 years ago with 20K miles on it and have taken it to a dealer for oil changes - so far as I know they never mentioned the need for transmission fluid service. And the official consumer-level Ford maintenance schedule simply says to inspect the fluid and "consult with the dealer for requirements" every so often. It never struck me as odd to have a long service interval, because our 4Runner's first transmission fluid service came at over 100k - and it's always worked incredibly well.

 

We really like the Edge, but the transmission has always felt funny - like it's shifting at the wrong time or shifting roughly. We had a software update around late 2020/early 2021, but I'm not sure it changed anything. I'll likely take your recommendation in an attempt to prolong the transmission life. Thanks again.

[colinc755]

On 10/10/2022 at 1:44 AM, waflyboy said:

Thank you for your insight! It makes sense and I really appreciate you taking the time.

 

Unfortunately, our 2019 has 62K miles and I don't think the transmission fluid has ever been serviced. We bought it 2 years ago with 20K miles on it and have taken it to a dealer for oil changes - so far as I know they never mentioned the need for transmission fluid service. And the official consumer-level Ford maintenance schedule simply says to inspect the fluid and "consult with the dealer for requirements" every so often. It never struck me as odd to have a long service interval, because our 4Runner's first transmission fluid service came at over 100k - and it's always worked incredibly well.

 

We really like the Edge, but the transmission has always felt funny - like it's shifting at the wrong time or shifting roughly. We had a software update around late 2020/early 2021, but I'm not sure it changed anything. I'll likely take your recommendation in an attempt to prolong the transmission life. Thanks again.

Yeah I would be lying if I said I was not in a similar boat with general transmission quirkiness. My 8f35 still surges and bucks every once and awhile even after the software update. There is one hill near where I live that is pretty steep and has a 25mph speed limit up it, the car just surges between 1 to 2 and 2 to 1 the entire way up.

 

Mostly what it comes from is that Ford took a 6f35 and added a new gear between the old 1 and 2 and added an additional overdrive between the old 5 and 6. Problem is the 6f35 was notorious for already having a rough 1 to 2 so throwing another gear in there made the problem even worse. The new gears are so close to the old ones in ratio that the car cannot stay in them for long and has to jump to the next gear really quickly. If you let off the throttle during that process, it'll surge and buck. That is why the vast majority of issues are around the 25mph mark too, the overdrive gears in these are amazing.

 

What frustrates me the most is that Ford recognized this and converted the software in the 2022+ ST models to skip the new 2nd gear, making it an artificial 7-speed transmission. This has made the newer ST's amazing to drive, and Ford has no plans of porting that software to any older ST's or 2.0's so we are stuck. Keeping up on fluids will help those quirks just remain as quirks and not endless damage. 

[waflyboy]

To add to the conversation:

I visited our local Ford dealer yesterday and requested a drain and fill. The service writer said that it wasn't recommended until 150k miles, but I ask them to do it anyway. We also discussed the weird shifting (occasional "bucking" / hard shifting), and he started to mention all kinds of things that we could to try to correct that (at my expense, of course), but it really didn't sound like he was familiar with this complaint on the Edge. Ultimately, I just had the fluid changed (drain and fill, as discussed). I don't think they did anything with the software, but I swear it seems to shift smoother. Not sure if it's in my head or if the new fluid is helping. For what it's worth, the tech said that the existing fluid appeared "normal." 

Thanks again for the info and help.

[HellRat]

On 8/7/2022 at 11:04 AM, kruzr1 said:

Thought I would post this here as a comparison/reference.

Do you have a link or something I could get to the workshop manual, trying to do a fluid change on my 2109 edge st as well

Edited October 30, 2023 by 1004ron

[bigmac]

I was able to reattach the rubber funnel to the transmission fill hole using locking needle-nose pliers on the snap ring mentioned by Colinc755. This made reassembly quick after refilling the transmission fluid on my 2022 Edge. I was not able to use regular need-nose pliers for reassembly, only for removal of the funnel.

[colinc755]

10 hours ago, bigmac said:

I was able to reattach the rubber funnel to the transmission fill hole using locking needle-nose pliers on the snap ring mentioned by Colinc755. This made reassembly quick after refilling the transmission fluid on my 2022 Edge. I was not able to use regular need-nose pliers for reassembly, only for removal of the funnel.

That’s good to hear that my struggles with getting it back on weren’t just a lack of skill ?. There really isn’t a whole lot of room. 

[John 6567]

Hey I just want to acknowledge Kruzer1 Post on August in 2022. The 8F57 was a breeze in the ST (2019). 

 

Go under your car take the fabric cover off the driver's side you don't even need to remove it completely. 8mm I believe. Then there's the 14mm drain plug. Wait, take off the front most intake tube you'll see the breather and clamp attached to transmission. There's actually no videos or free documentation online so I was skeptical. Drained fluid, then poured a little ULV in the 1 inch hole. You need channel locks to get it off. Waited a minute and it trickled out. Great. 

 

Measured what came out with old gallon containers of coolant. About 5.5qt bought the 6 pack so it was perfect. Wished I did have 7qt though. Locked back up. Already have a monitor so it did take 20 min to get the transmission around 200. The slipping in 5th or 28-38mph is gone. I did reset the learning too though so it's debatable which helped more. Old fluid was dirty so it surely helped.

[bogmanglen]

Thanks to Colinc755 for a terrific write-up.  As so often happens, knowing that a problem like this is coming gives you plenty of time to think about solutions.

 

I was able to grab the snap ring with needle-nosed vise grips, and lock it open.  The funnel came right off, and was readily re-installed using this method.

 

On another note, am I OK to drain the fluid cold, then just add the same amount back in cold?

Thanks