Hello everyone,
I just bought a 01 expedition (2wd 5.4 with the 4r100 with about 136k on the clock) to tow a small utility trailer across the country. We left southern California a few days ago, and when we got to Phoenix we tan into some trouble. We hit traffic in 110° weather, and I could really hear the fan clutch locking up in the stop and go, but what I noticed more is the smell of trans fluid. We got off the freeway and to my wifes cousins house where I saw a trail of atf on the road where I pulled in.
I'm new to Fords, so upon further research I found out the factory trans pump seal likes to puke fluid when it gets hot. I lost a few quarts so I let it cool while I went and picked up some more mercon v, refilled it and hoped for the best. All was good! Untill we got to Santa Fe... that's when I realized its leaking in city/stop and go conditions, but here's the kicker, its only with the trailer attached.
I only lost a 1/2 quart in Santa Fe (caught it now that I'm looking for it) but we pulled into our friends house in Tulsa (where I might drop the tranny and replace the seal before driving the rest of the way to PA), and sure enough after getting off the freeway and driving surface streets it started to leak. I let it cool, topped it off, unhooked the trailer and we went out to dinner. We drove all around Tulsa without the trailer and without leaking. So now I'm kinda questioning if the seal is just borderline going bad and the small trailer is causing just enough more heat (trans and engine working harder) just enough to push it over the edge, or is it something more serious like the TC dying from the extra weight?
I noticed heavy braking really exasperates the problem. could it be fluid is sloshing violently to the front of the trans under heavy braking making more come out of the pump seal? Or is th TC losing it from the rapid change in pressure and hauling the extra weight?
I was a mechanic in another life, and did a few trans rebuilds, but that was almost 15 years ago and I'm a little rusty. I also have very little money, and 1200 more miles to drive, so taking it in to a shop is out of the question.
Does all of this sound like the infamous seal? I was thinking about installing a big aftermarket trans cooler to see it that keep the temp low enough to get us there. Anyone try that as a bit of a bandaid fix?

 

The weight of the trailer, combined with stop and go in high ambient temperature, is probably enough to get the seal hot. When it's too hot it gets soft and leaks. Once it cools, it seals again. It usually can do many cycles of this until the ultimate failure.

It leaks into the bellhousing. The fluid can puddle there and then leak out onto the ground during heavy braking. Heavy braking cannot make the seal leak more than any other time.

If you do replace the seal, get an aftermarket seal made from a material called Viton. It's MUCH better than the stock seal. A Ford dealer is unlikely to have this improved seal.

While it's out you MUST inspect the bushing right behind the seal. If it shows any wear it is probably the cause of the seal leaking. Replace it. Also carefully inspect the machined end of the torque converter. This is what the seal rides on. If there is any imperfections the new seal is going to leak, too.

 

Thanks for the reply Mark. Glad to hear you sound sure its just the seal. Yeah I've been reading up on this pump seal issue, and I plan on resolving it asap. My issue is we're saving money we don't have by staying with friends and family along the way, and I feel kinda bad asking for a place to crash AND drop a huge leaky transmission all over their garage/driveway lol!
with that being said, I was going to do a flow test along with a fluid/filter exchange to be sure flow isn't impeded just a little. And if it is, I was thinking that fixing the block (if there is one) and getting a bigger aux cooler (even if thats not the site of a potential block) might keep the temps down just enough to keep the seal somewhat happy the rest of the way to PA.
Any chance that might help? We've been driving all over the place the last couple of days, city and highway, with the trailer unhooked and it hasn't dripped a drop. That's why I wonder if the seal is border line failing, and dropping a few degrees might help keep it from crossing that line when we re-hookup. Does that sound like sound logic, or am I grasping at straws here?

 

Oh and I have one more question. If I end up having to do the seal/bushing before we get to PA, is there a brick and mortar place to get a good kit with the viton seal? Every search comes up with ebay or some other online source, but I don't exactly have an address, or time to wait on shipping right now. Someone posted a viton seal at napa in another thread, but they don't seem to have the bushing. Could I just get that at any Ford dealership? And if so, is the oem bushing ok to use? Thanks again

 

The OEM bushing is fine.

Better cooling might be enough to keep the current seal from leaking.

 

I'll give it a shot, and try to post up results should future long distance drivers come across the same issue. Thanks again

 

So as I stated before, I'm new to Fords, and when installing aftermarket trans cooler, I found the magnefine filter (didn't know about them until this point). I did a little research on it, got a replacement, and when I pulled it out it was almost completely blocked. I was reading how these blocked filters can overheat trannys, and I bet thats why I was having trouble with my seal leaking (besides it inherently being prone to leak). I'm in no position right now to get it rebuilt, so I flushed the radiator, trans cooler/lines, installed the external cooler, I'm gonna replace all the fluid per Marks how to, then pray, cross my fingers and hope I didn't fry the tranny so bad that we're stuck over 1000 miles away between our start and finish points!
So given that the filter was almost completely clogged, would that open the bypass AND cause more internal pressure causing the pump seal to blow fluid even easier?
I'm wondering if now that I have good flow, and a MUCH cooler running system that the seal might not give me as much or any trouble. That's assuming I didn't fry my trans :-|

 

A plugged filter will open the bypass. When the bypass is open the pressure is not higher. Pressure is regulated, so it's constant. The higher temperatures will cause the seal to leak, not more pressure.
That's likely.

Did you get the trans over 300F? If not, you didn't fry the trans. If you did, it's possible, but not likely.

 

So I dropped the pan and it was relatively clean except for this






I dont have much experience with slush boxes, but I know its not good, any idea where it broke off of? Its about 1/4" long by about a 1/16"
I usually wouldn't ask, I would just have rebuilt after all its been through, but I'm in a tough spot. If anyone has an idea what it broke off of, and if it might make it from Tulsa Oklahoma to eastern Pennsylvania.

 

I don't recognize it.

 

I don't have a temp gauge, so I have no idea what temps it saw. I know it got pretty hot though.
So I decided to finish the fluid replacement and hope for the best, and its running really well. I do feel at idle a very slight, even border line unnoticeable shudder, which I'm thinking might be the torque converter. it was worse with the overheated fluid. But overall it feels great, even after about 40 mi of stop and go city driving.
As far as the little metal chunk, I'm still concerned. However the way it's driving is giving me the confidence to drive the rest of the way.
The next test is with the trailer hooked up, but I can already tell its running MUCH cooler, and it hasn't dripped a drop yet, even after some long idles mixed in with stop and go traffic.
I did install a new inline filter, but I was reading a lot of people are deleting them for this very reason. Is that a good idea?

 

I can't imagine a way the torque converter could cause that.
I have mixed feelings on it. If it doesn't have too much restriction it should be fine. How much is too much? That's the problem.

 

I don't know either, other than reading people saying switching from Mercon to Mercon V got rid of some sort of a torque converter noise/vibration. I just assumed it maybe had some sort of friction modifier that smoothed it out or something to that effect. Maybe I was reading something else? Again, I don't have much auto trans experience.
Its flowing pretty good now, but I want it to stay that way, that's why I kinda want to delete ithe inline filter from the system. I might just leave it in the rest of the trip, and check the flow again when I get there.
Again, I'll update the post on how it turns out, and Mark thank you very much for your help and info!

 

Torque converter shudder is possible, but only when it tries to lock. That doesn't happen until about 40 MPH, not at idle. The torque converter can't cause a shudder at idle.

 

I have built 87 bazillion transmission and do not recognize that piece of metal.
Is it hard like part of a bearing race?