2013 Transmission Flush

[ErichExplorer]

My 2013 has about 84k miles and based on many of the threads I have on this forum I decided to do a flush of the transmission fluid. I tow a snowmobile trailer about 175 miles about 8 to 10 times a winter so I figured no harm in doing a flush at this point.
This weekend I drained 4.5 qts of fluid from the transmission drain plug and added the same amount back in the dipstck tube. Quite simple. That is until I started the engine again. As soon as I started the car I heard a loud, very concerning thunk. This was followed by two terrain management faults, the traction control “off” light coming on as well as the traction control fault light coming on. And just for good measure, the check engine light came on as well. So I was now staring at five warnings in my dash. I let the car idle for a few minutes and shifted into R - another very loud thunk, I shifted slowly into N - another loud thunk. I shifted slowly into D - you guessed it, another loud thunk.

The same thunks repeated on the way down back to P. I checked the fluid level with the engine running and it was perfectly centered in the middle of the Hash marks. I shut off the engine, waited a few minutes and then started it again. The same thunk repeated in startup as well as the same thunks moving through the gears.

I have read many posts and watched many YouTube videos about draining and filling transmission fluid in this car (I used MC Dextron LV) and there is not a single mention of anything like this happening.

So I now fear I have taken 100,000 miles of life out of my transmission. I can’t figure out what I have done wrong.

I have exchanged the fluid in the PTU in this car without issue, which is much more complicated than the transmission fluid exchange. Also, the Explorer transmission seems much, much simpler than the BMW and Jaguar transmissions I have completed without a single issue.

Is there a critical step I missed in what seemed like a simple process of draining some of the transmission fluid and filling the same amount back in?

 

[Crates]

I just did the drain and fill on my 2014 - followed the same process as you but had no noise at all afterward. Which plug did you remove? I recall seeing a couple under the trans. Or possibly something fell inside while you had the dipstick tube out?

 

[blwnsmoke]

Odd, I've done my trans last fall with no issue as well. I am not sure what could have happened by just a drain and fill.

 

[ErichExplorer]

Which plug is a good question. There seem to several to choose from, but the one that made the most sense to me is the one that is at the lowest point on the transmission and was closest to the front of the vehicle on the left side. That's the one I used. I also went on youtube and it seems that is the correct plug.
I am 100% sure that the only thing that went into the transmission is pure MC Dextron LV.

 

[peterk9]

If a transmission is in 'Park' when the engine is started, is it not in an idle position? I thought it only becomes 'active' when put in gear. If so, I don't know why it would produce that "thunk" or any noise? I'm obviously not a mechanic.

Peter

 

[ErichExplorer]

That is exactly what I thought. Why in the world would the transmission thunk while the car is in park?

As a follow up: I let the car idle for a long time after the first few times of starting and shifting with the big thunks - this time it shifted into Drive without a big noise. I drove it about 5 miles with all the warning lights and it went down the road, but the shifting was very clearly far from smooth. I shut it off for 10 mins and upon restarting, all lights and warnings (except check engine) were gone. The car then drove normally. I cleared he engine light and it stayed off.

Based on this experience, I do not plan to complete the next two drain and fill sequences that will amount to completely changing the fluid in the transmission.

 

[03WIExplorerLtd]

Goto Autozone etc and see if you get a code. Don't know if those will come up on their tool. I have a forscan compatible reader, all in like 35 bucks. Gets any code.

 

[whimsey]

The drain plug is on the underside of the transmission, can't miss it. It takes an 11 mm socket. It looks like a plumbing plug and has thread sealer showing usually as well as some of the treads on the plug. At least the one on my 6F35 transmission. What I could see is the drain for your 6F50/55 should be the same, at least for model year 2017. I don't know if your model year is different.

Whimsey

 

[ErichExplorer]

Thanks guys. @ Whimsey, I pulled the plug you described. It was clearly ATF that came out.
As far as the codes, I have code readers and actually did read the codes before I cleared them - there were two of them. I didn’t bother looking them up because I figured I knew the issue. If they come back then I will be singing a different tune.

 

[KayGee]

A common cause of clunking is low fluid (my 6f55s dropped 5 or 5.5 qts, not 4.5). Could also be deposits that loosened up due to new fluid, wear that was masked by older/thicker fluid, or any other number of things. Some people swear by seafoam trans tune before a flush/fill and others don't. Did you disconnect battery or otherwise reset the trans when you did the flush/fill?

 

[ErichExplorer]

KayGee, no I did not disconnect the battery or do any type of reset. Is there a procedure I totally missed? I have a 6f55 transmission as well. It was a little low on fluid before I did the first flush, but not a whole quart low. I added a little more than I drained and the level is now centered in the hash marks.
I was thinking, I drained the fluid when everything was hot. I had just run it up to operating temp and run it through the gears to check the fluid level before I drained it.
Should the drain and fill be done with everything cold?

 

[Jon M]

If everything is running normally now, and you want it flushed, you might just break down and take to a shop or the dealer. I did my '13 at 56k, but I wanted it fully flushed by machine. For $180, it was worth every penny. I'm at 50k on the '15, and it's going to be done shortly.

 

[Explorer75]

I would add more fluid, 1/4 quart to start. That noise sounds like low fluid. The level on the dipstick can only be read with the transmission hot (between 180F-200F). About 10 miles of city driving should warm it. I use Torque Pro App with a Bluetooth ODBII transmitter to know the temp.

 

[KayGee]

KayGee, no I did not disconnect the battery or do any type of reset. Is there a procedure I totally missed? I have a 6f55 transmission as well. It was a little low on fluid before I did the first flush, but not a whole quart low. I added a little more than I drained and the level is now centered in the hash marks.
I was thinking, I drained the fluid when everything was hot. I had just run it up to operating temp and run it through the gears to check the fluid level before I drained it.
Should the drain and fill be done with everything cold?

If you reset the trans memory, it can cause the shifts to change until it relearns as it goes back to defaults. I've changed fluid hot and cold. I usually gauge how much to put in by how much comes out to start and than adjust from there once hot. I run my fluid levels closer to or at the full mark typically.

 

[Explorer75]

If everything is running normally now, and you want it flushed, you might just break down and take to a shop or the dealer. I did my '13 at 56k, but I wanted it fully flushed by machine. For $180, it was worth every penny. I'm at 50k on the '15, and it's going to be done shortly.

Good deal. I did my own "flush" by doing 5 drain and refills, waiting a couple of days between, at the end I have about 94% of new fluid. The last drain the fluid came out cherry red, seem like new.

 

[KayGee]

Good deal. I did my own "flush" by doing 5 drain and refills, waiting a couple of days between, at the end I have about 94% of new fluid. The last drain the fluid came out cherry red, seem like new.

25 qts. That's a lot of fluid to "waste". You may be better off having just done a single drain and fill each year. Or, you could have just had a dealer do it for you.

I got 10 cases of mercon lv a couple years ago on clearance at ~$2/qt and I would never entertain wasting 25 qts like that. I usually just do a drain and fill yearly or maybe 2 every other year.

 

[Keith N]

I did a drain/refill twice this past fall. Genuine Mercon fluid was only $5/quart delivered by Rock auto. Bought 10 quarts. I drained it warm, and got 4-4.5 quarts each time as I recall. I had a really hard time figuring out the level on the dipstick. I am pretty sure it was slightly low at first, but car drove normal. Then checking it thru the week, I added more, and it was too high. Still drove fine. No clunks or bangs at any time through all this. I drained and refilled it following weekend and still no issues. I slightly overfilled it and pumped a little out to get it to proper level. Point is I never had any clunks or bangs and got a good share of old fluid out for $50. What you had happened sounds unusual.

 

[Explorer75]

25 qts. That's a lot of fluid to "waste". You may be better off having just done a single drain and fill each year. Or, you could have just had a dealer do it for you.

I got 10 cases of mercon lv a couple years ago on clearance at ~$2/qt and I would never entertain wasting 25 qts like that. I usually just do a drain and fill yearly or maybe 2 every other year.

How many qts for a flush?

$125 is cheaper than $180 anyway. It´s also an option for someone like me who likes to DIY most of the work on the truck. Also I haven´t seen a place with a flush machine in my country, maybe the dealer has one and they won´t charge only $180. Maybe 180 plus the fluid.

 

[RhinoQuartz]

So, uh, there's a whole lot of talk of replacing what was drained, but has anyone checked their owners manual, under 'Capacities and Specifications' to check how much fluid your transmission takes?

 

[Explorer75]

Workshop manual says to add 4.5 quarts after draining. Afterwards you need to warm up the trans to 180-200F and check level.

He filled with 4.5 qt, my guess is somehow he's still low. He mentioned he drained while the transmission was hot. I don't know how hot it was but maybe that has something to do why he could be low. I always drain in a cold transmision or well below the 180F mark. Did he drain while the trans was over 180F?
That's the question. With the symptoms he describes I would add 1/4 of a qt and check.