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4F50N Transmission Problem (Extreme Detail)

19K views 58 replies 8 participants last post by  Sam 
#1 · (Edited)
Ok, so get ready for this one. I am new here (hi everybody). Ok, so here is the story. I bought this 2000 Taurus SE off of a friend for $300, 110k, engine working, but the transmission had been acting weird. You put it in overdrive, and it goes to about 25 or so and then starts bouncing off the powerband. Like as in, you could clearly tell that nothing was engaging. Now when I was test driving the car, if I was to just simply press the gas harder, the car would then move faster. I got the car up to 65 once when testing it (I know, bad idea), so I don't know if there are any internal problems. The only way I got it to go that fast was if I was in low gear by the way. Weird, huh? Alright, so then I came home and completely started taking stuff apart. I had to find a way to pull the valve body cover without dropping anything that I didn't need to. Needless to say I found a way. I unbolted the tranny mount and took it off the car along with the big piece of metal that connects it from the tranny to the body. So I pulled the pan off, and then the next day I took off the valve body. I took some pictures of the pump shaft, and nothing on it looks sheared. I then looked into the hole towards the TC and I didn't see anything out of the ordinary. I then started cranking over the engine with a ratchet to see if the shaft was turning, and it was, so yeah. Now here I am on this forum for the first time, asking what might be wrong. I tried to do research before, so I could get straightforward support. What could possibly be wrong here. Something in the valve body? A sensor? I'm really new to this new transmission technology. I will attach photos here too. I have NOT checked the solenoids YET, that's tomorrow. I turned the pump with the shaft in by hand and it turned fine. I did NOT however, check the pump when It was all together. Oh yeah, The fluid smelt burnt a little bit, not a horrible smell, just a bit of burnt smell.

Car details
2000 Ford Taurus SE
3.0 Vulcan, 4F50N
110k Miles




 
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#3 ·
Well before pulling it out I would have done a fluid and filter change.

Check the shift solenoids. Can you leave it in D and get it to 65 just fine? It's only when in OD? Metal shavings in the fluid?


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#4 ·
I would disagree with the "extreme detail" description. Perhaps it contains extreme ignorance instead.

No mention of gears here (there are four) so was the transmission even shifting or were you stuck in 2nd gear?

Generally you do the electrical checks and the line pressure checks before you rip the valve body out of the transmission. Are you sure you weren't just low on fluid?
 
#5 ·
Well the person that I got it from said they changed it, but the bolts on the pan looked like they hadn't been touched. As for the gears, If I leave it in overdrive it will only go up to 25 no matter what I do. if I shifted into low gear it will go up to 65, after playingwith the throttle a bit, like you have to press it pretty hard to get it to hook up. And I very slightly felt the transmission shift down when I was de-accelerating. It's a whole new work, this automatic transmission. For me at least. I'm at work now but I'll check all the solenoids and the TCC solenoid when I get home.
 
#6 ·
When I say "shift" I mean what is the transmission actually doing, not where you have the gear selector (you said it shifted once on decel). You should be able to roughly figure out what gear it's in by comparing the engine speed to the vehicle speed.

When you hit your max speeds of 25 MPH and 65 MPH, what was the tachometer reading (like what number was it pointing to)?

Was the check engine light on at all or were there any codes?

If the transmission was slipping in third gear to 65 MPH at WOT it's very possible you completely burnt the fluid that was just changed in addition to severely wearing what was left of the clutch disks.
 
#7 · (Edited)
First off I wasn't even responding to your question. You would have to put it into low gear when you hit that 25 miles an hour and then mash on the gas and then it would slowly make it to 65. You would never feel the car actually shift at all but that would make any sense if you're going 65 miles an hour in first gear. Something would've had to shift. Now 65 isn't the top speed, I just didn't want to run the piss out of the transmission if there was an internal problem. And please don't call me ignorant I'm not really ignorant I just don't know anything about automatic transmissions. I forgot the obdii codes, but One of them was for an EGR restriction and the other one was for an O2 sensor. As for the shifting down I was driving at 65 miles an hour in low gear let off the gas and at about 25 miles an hour the car had a slight thunk back into some gear I don't know what one. So I don't know If it's my pump not working efficiently enough to make the torque converter work I have no idea. I would have to Have the RPMs be like over 4000 in order for my Car to go any faster.
 
#10 · (Edited)
Okay gentlemen lets not call people names. FYI most people say this forum is very welcoming. Also, behlinla is one of the best resources on this forum.

Behlinla - lay off.

Nonstop - dont get mad, ignore it if you don't like it. I edited your post. Behlinla did see it.

Anyways, I think we still don't understand what's going on here.


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#11 · (Edited)
Okay. So if you can post the exact codes that would be very helpful! I would put the trans back together and drop the pan and do a fluid and filter change.

Drive it more and pay attention to when each gear shifts and what gear you are in. If it is in OD, and you lightly press the pedal, will the rpm's keep moving up until you reach 4000? Or 6000?
 
#12 ·
I never felt it shift when I drove it last. Maybe stck in 3rd? And those codes will come in a couple hours. And I have full synthetic waiting to go in with filter and gasket. This is what pretty much happens from start to finish when i was test driving the car. I would put it into overdrive you know driving normally and then I would hit the gas it would get to 25 mph and then it would start acting as if the clutch was slipping off or something like that. So then the RPMs would go to like 6000 with nothing so then I shifted into low Gear and then it would start moving again I would really have to press down the throttle in order for my car to move anywhere. It would only and I say only go through 25 mph in drive and in overdrive which makes me think That a solenoid is out and is throwing the binary code out of sync in the transmission which is making the transmission shift into a gear that it is not supposed to be in.
 
#13 ·
Sounds to me that the slipping is happening in third gear. 25mph under light load is when it shifts into third. Too slow for OD.

Making sure: so in OD it does the same thing as in D. It's only when you drop it to 1 that you can drive up to 65. At 65mph were the rpm's at 6000 or so?


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#15 ·
Check to see if your DPFE hoses popped off or melted.

It is quite possible this isn't a transmission problem at all.

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#17 ·
Correct. Interesting. Replace it and see if the code goes away (p0401).

Someone else needs to chime in on the trans now.


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#18 ·
Well I'm going to go assemble everything back together and see what happens. If anything I got ALOT of bad looking fluid out, so that's a plus! I'll then drop the pan and check for shavings, or well, hunks, hopefully not!
 
#19 ·
Removing the VB cover, with the drainige happening, may only get a couple of quarts out depending on the angle of the trans.

If you drop the pan, you'll change another 7 to 8 quarts.
 
#23 ·
It sounds like some other electrical issue is causing your problems. When you say you shifted to Low range, do you mean you placed the trans in "1" or "D" instead of "D" surrounded by the "O" (over drive)?

Also, is there any other weird electrical issues? Example, radio not working or, turning the headlights on causes the turn signals to light up solid?
 
#24 ·
When I say low gear, I mean manual first, like gear selector all the way to the right. I had thought at one point that it might be a TR sensor or something along those lines. I did, however, check all the solenoids and they all checked out fine as far as I know. I have everything almost put back together. I just have to reinstall the transmission mount while will be a pain considering I took the whole mount off to be able to get the valve body pan off. Updates tonight.
 
#26 ·
^
That's happened to me more than once. Well not with taking the transmission apart, but with other things. You think I would have learned my lesson by now, but EVERY time I take the back seat off, I ALWAYS bolt it up then realize I left the seatbelts behind it! I did it tonight and got so frustrated lol. EVERY time (out of like 6 times I've done it).

Hate it when stuff gets put back together then you have to take it apart again. Good luck!

P.S. Make sure to put only Mercon V ATF back in!
 
#27 ·
Yeah, I got to the valve body and went to bed, haha. Then I started thinking, "how the hell am I going to get this transmission mount back on?"
Well I unbolted the frame from the car and lifted the front of the car up with a jack and a piece of wood. Easy enough. But just a general question, what's wrong with putting ATF+4 Full synthetic in?
 
#28 ·
The trans is spec'd for mercon V. They are picky about their fluids. Don't put anything else in. It can damage it.
 
#29 ·
Alrighty. Hey, whilst looking over the valve body and putting the check ball in and making sure everything was perfect, I saw one orange spring. All the rest were black. Here is a picture.

Has this been worked on before or is it just coincidence?
 
#31 ·
I hope taking apart the trans was a learning experience for you! That spring almost looks rusty. Remember. MERCON V ATF ONLY!
 
#32 ·
Well I've never done an automatic transmission before. I'm not saying it was easy, because it was not! Haha! And we'll, as for the spring, it's too late now, all put back together. The dash is lighting up, so I think all is good. I'm gonna let the transmission drain overnight. And yes, I know! Mercon V! Is the super tech stuff good?
 
#35 ·
That's SUPER low. Should have 7qts or so in the pan...

You will need to add 9 quarts or so since you had the valve body off. Please don't overfill it though. Make sure once you have enough in to let the car idle till it reaches operating temp (don't drive it please), then check the fluid level while it is idling. Should be just below the top of the cross hatch line.

Supertech is great!
 
#39 ·
...wow...just wow. That's a mess. I'm surprised the magnet managed to hold all those shavings and related gunk.
 
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