2002 Ford F150 (Auto, 4x4 Lariat, 5.4L) - ATF flush (178K miles)

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I have tried to research this, but finding conflicting info - and have a question I can find no answer for.

1) Some say it's not wise to flush with this many miles, as it risks dislodging bits that can be bad for the tranny. So just drop the pan replace the filter and replace the 4-5 quarts that come with the pan - then do the same again later, to work out the bits over time and replace more of the oil in the torque converter, since they quit putting a drain plug there with 2001 models.

2) Some suggest disconnecting near the cooler - start the engine a bit, until line sputters, then drop pan, replace filter, and seal it back up, and refill - and then run a bit more and make sure refilling until you get to all good fluid, then close it back up, run it a bit, go through the gears, then top off.

Current pan has no drain - replacing it with one with a drain plug. I thought I would run a quart or two of transmission flush through the system, then drain it, but without a drain plug, not sure how to really pull that off - which leads to the question I couldn't find an answer for.

3) With ATF being so pricey, I was wondering if I could drain the system (like in 2 above), drop the pan, clean the magnet, etc. put it back in place, and fill with the flush and 0w20 motor oil - just to use as a flush, just to be able to run most of the spent ATF out, run just a few miles on it, enough to go through the gears - with the flush fluid, then pull the pan, replace the filter and install the new pan (with drain plug). Then make sure all the motor oil is flushed out with the red ATF.

Just trying to do what's good to clear out as much old fluid, etc. out. In chemistry, it took three rinses to get contaminants low enough to not compromise what more would be done. That is in the back of my mind - and good 0w20 synthetic motor oil - to use as a part of the flush is far cheaper than ATF fluid, to use as a couple of flushes. Typing out loud aiming to be smart and practical about this. Thanks for any help the informed and wise in the forum about this have to offer.
 
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3) With ATF being so pricey, I was wondering if I could drain the system (like in 2 above), drop the pan, clean the magnet, etc. put it back in place, and fill with the flush and 0w20 motor oil - just to use as a flush, just to be able to run most of the spent ATF out, run just a few miles on it, enough to go through the gears - with the flush fluid, then pull the pan, replace the filter and install the new pan (with drain plug). Then make sure all the motor oil is flushed out with the red ATF.

I recommend finding a reputable shop and having the transmission serviced. Motor oil does not belong in a transmission.

Edit - shops have specific machines that can swap fluid in your transmission without the mess and fuss. It really doesn't cost much more than doing it yourself. Having been a mechanic a long time, the fact that you want to add motor oil to your transmission is concerning and sometimes, these procedures should be left to the experts to maintain component integrity and reliability.

Welcome to the forum.
 
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WileEC_ID

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I recommend finding a reputable shop and having the transmission serviced. Motor oil does not belong in a transmission.

Edit - shops have specific machines that can swap fluid in your transmission without the mess and fuss. It really doesn't cost much more than doing it yourself. Having been a mechanic a long time, the fact that you want to add motor oil to your transmission is concerning and sometimes, these procedures should be left to the experts to maintain component integrity and reliability.

Welcome to the forum.
I think you misunderstand - it's not that I want to add motor oil to the system - but I do want to clean the system and a parked truck holds onto plenty of fluid that won't be touched in the typical machine flush, or the typical drop and drain.

From all the research I've done - the basic difference between motor oil and ATF is additives - very different package for each, since the demands are very different.

Never had a tranny or motor issue with any owned vehicle - aim to keep it that way.
 
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If you want to clean the system and replace the old fluid, adding a dissimilar and non-compatible fluid is not the way to go.
Mercon V can be found at Walmart and is relatively inexpensive. Adding motor oil to a 4R70W will damage it, so comparing fluid prices is moot.
 
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You want to do sort of a combination, drain the pan, change the filter, install pan and fill, then disconnect the return line from the cooler, then exchange the fluid in short duration's letting the motor run to use the transmissions pump for fluid exchange; this example uses: over fill 1 quart; 2 quarts out, 2 quarts in. This video is where I learned this process;

I've used the above example until the last than just add the last quart in increments to get an exact fill level. I'd suggest buying 2 extra quarts over the expected exchange volume, for example last time I had 10 quarts on hand and I should have had 14, because I needed 12.

Your getting most of the dirt out from the pan and the fluid coming out the return line has been through the filter, it's just most of the rest of the volume from the transmission and it is darker but you should start to see cleaner fluid when you've exchanged the recommended volume, nothing bought is wasted and there is no need to run any other type fluid to flush the system.

To clarify on dislodged bits, that's sometimes what can keep a worn transmission working as it fills in for the material worn off the clutch plates and that why some would warn you not to change the fluid. I've changed fluid on Toyota's with more than 200k and join in the opinion of the transmission is already on it's limits of use if a fluid change bring on the demise sooner.
 
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Problem with adding motor oil, even as a flush, is that there's more in a transmission than just metal parts. The fiber clutches are going to absorb that oil and you most likely won't be pleased with the results. Keep the motor oil where it belongs and if you're absolutely wanting to run clean fluid as a flush, I would just find the cheapest thing that meets spec, run it through, and then change it out to your 'good' fluid.


If it were mine, at 178k with an unknown history. Change the pan and filter (Adding your drain plug), add fluid, drive for a few hundred miles, and then D&F. Repeat that a few times and roll with it.
 

WileEC_ID

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I really appreciate all the replies - they confirm what I was thinking was the better option - not to flush with motor oil - but just be smart about flushing with ATF and have some extra on hand. And, once I have the drain plug, it is a lot easier to do any part of this again.
 

WileEC_ID

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I thought I would post a follow-up, now having completely the initial drain and drop - kind-of. I had researched best practice from a number of sources - and discovered there were helpful bits that were not repeated by more than one source - I will include all of them here. These are mostly the tips, not all the steps - that are fully covered most places anyone finding this will have already found.

1) Start at the front of the truck - once the rock guard is removed - I disconnected the transmission line from the cooler (that comes from the pump). In my case it is the second one from the passenger side. First one is out from the cooler, second one over is from the pump. Some fluid drains here so be prepared for that. Then I put the end of the hose into a five quart oil jug and had my wife start up the truck - we ran it the several seconds it took for there to be no more fluid pumped, then stopped the truck. You can reconnect the transmission line at this point.

2) Remove the transmission drain pan - it is basically drained, so the waterfall of fluid shown in most YT videos covering the topic is no issue. Tip one came from a tech in another forum and is the key to this no mess pan removal. There was still around a quart of fluid left in the pan, so be mindful of that as you get it down. One quart versus 4-5 makes a big difference in how clean this part is accomplished. Still need a catch can for the odds and ends that will drain from the transmission parts above the drain pan.

3) Once the pan is down and you have wedged off the oil filter - be sure to remove the rubber gasket from the transmission for the old filter. It seems these orange rubber rings of a gasket like to stay in place. Be sure to remove it before you install the new filter (with it's new rubber gasket).

4) Be sure to clean off your magnet, the pan and remove the plastic top, if you have one - no need for it. Thankfully for me, no "top" and my magnet and fluid looked quite good relative to the YT videos of trucks with similar miles.

Relative to my original query about using motor oil as a flush - I did not do that - clearly not the best of ideas - but you don't know if you don't ask. I have enough fluid to flush it three times - where one is only getting around 5 quarts out at a time. That should clear out most of the contaminants and give this old automatic a good chance of staying reliable. I did replace the drain pan with one that has a drain plug - that will greatly simplify and speed up the process in the future.

Sad there seems to not be a DYI method for draining more of the fluid at once. Given the pump drains the pan and when you fill, it is going directly into the pan (you can see the end of the dipstick) - any fresh fluid added is going to just get pumped right back out. It seems regular drain and drop is the key to minimizing contaminants in the system.
 
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