Truck lurches forward and stalls when going into forward gear. Sticky TC? Or worse?

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Expe101

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Hello everyone, new guy here. (intro post: http://www.expeditionforum.com/f50/new-guy-here-south-ga-19503/ )

I have a slight but serious problem. I just finished sea-foaming my 4.6 and just finished "driving it hard" to blow out any junk build-up, came to a stop, and the truck stalls. I put it in NEUTRAL, cranked it back up, put it in DRIVE and it quits. (It acts like the trannys still engaged because wants to lurch forward.)

The same thing happens in 2ND and in 1ST. When I put it in REVERSE it bogs down a bit (500RPM) but settles out to 700RPM and idles fine. REVERSE does not make the motor quit.

If I come to a stop slowly (from 60MPH) I can feel it downshifting through each gear. (As well as see the RPMS change as it downshifts.) When it comes to a full stop it will bog and (if I stop it slow enough) disengage to where I can idle in DRIVE. When it downshifts it doesn't do so until 600RPM or so. If I stop too fast, it bogs and stalls.

The truck drives fine, up shifts through all the gears fine, OD on or off works fine, manually changing from 1ST to 2ND and then into DRIVE works fine.

Lastly, when I am IN OVERDRIVE, tap the brake, then press the accelerator, it revs like normal (2000RPM ish) until I get back up to the speed I want, THEN as I back off on the gas it finds OVERDRIVE and works like normal. ^ This all seems to be working and normal, just wanted to put this info out to possibly help.

Its just when I am in ANY gear it seems to stay in that gear until I get slow enough that it has to downshift. I had a guy tell me that it could be my planetary gears. Forgive me but I don't know what those do.

One more thing, I can hear something rubbing (metal on metal) right behind the motor. This does NOT happen all the time, just randomly. (at idle or low RPM) It might happen at higher RPM, I just cant hear it. I'm assuming this is the TC. I have plenty of tranny fluid, its still red/clear, (not milky or grayish) and the tranny itself is not slipping. Could it be something electrical? I did disconnect the battery for a few min the re-connected it but that did nothing.

Any advice would be greatly appreciated. (except for "take it to a tranny shop")
 

Jeff532003

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Any codes? That could really help. As far as metal on metal sound that doesn't sound like a torque converter whine. Search it up on YouTube to hear what one sounds like on its way out. Tranny fluid isn't foaming is it? I find it odd that this happened when you seafoamed it. It could be coincidental but I almost wonder if you used a bit much and fried a sensor somehow or something. Wish I could point you in a more definitive direction. Hopefully someone else might think of something I'm not.
 

toms89

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The pcm has control over when the tranny shifts and torque converter lockup.

Have not heard of a torque converter not wanting to unlock. I am thinking sensor as well but cant imagine which one or how the seafoam could have effected it. It shifts and controls the tranny based on throttle position and speed but it also uses a turbine shaft sensor to determine if the converter is locked.

Output shaft speed sensor,Turbine shaft sensor, tps sensor?? I think you could eliminate output shaft sensor as your speedo would be off as well.

What concerns me though is the metal on metal noise?!

What was the process you went through when you seafoamed it? Where did you put in the seafoam?
 
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Expe101

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Any codes? That could really help. As far as metal on metal sound that doesn't sound like a torque converter whine. Search it up on YouTube to hear what one sounds like on its way out. Tranny fluid isn't foaming is it? I find it odd that this happened when you seafoamed it. It could be coincidental but I almost wonder if you used a bit much and fried a sensor somehow or something. Wish I could point you in a more definitive direction. Hopefully someone else might think of something I'm not.
Ill get back with some codes this evening. The metal on metal sounds like a steam locomotive a chshhhh sound thats in time with the motor. (it sounds like its coming from the rear of the motor as well.)

I sea-foamed the motor. (Then drove it hard)
I seafoamed the tranny back in Aug. of last year. The hot level is at 1/4" or so over the cross hatches on the dipstick and runs red and clear. (idk why but the level doesn't change much when its cold...) My dipstick doesnt have a "hot" or "cold" level. Just some crosshatches an inch and 1/2 above the bottom tip.

The pcm has control over when the tranny shifts and torque converter lockup.

Have not heard of a torque converter not wanting to unlock. I am thinking sensor as well but cant imagine which one or how the seafoam could have effected it. It shifts and controls the tranny based on throttle position and speed but it also uses a turbine shaft sensor to determine if the converter is locked.

Output shaft speed sensor,Turbine shaft sensor, tps sensor?? I think you could eliminate output shaft sensor as your speedo would be off as well.

What concerns me though is the metal on metal noise?!

What was the process you went through when you seafoamed it? Where did you put in the seafoam?

Ok so you think it could be one of the three sensors you mentioned. Im guessin that one of those would throw a code? The noise is like I mentioned, sounds like a steam locomotive a chshhhh sound thats in time with the motor. (it sounds like its coming from the rear of the motor as well.)

I was seafoaming the motor. Sprayed the stiff right into the intake. Tranny has had seafoam in it for the past 7 months or so.

I will get a video of what the truck does later this evening, as well as the codes it throws.
 

toms89

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Ill get back with some codes this evening. The metal on metal sounds like a steam locomotive a chshhhh sound thats in time with the motor. (it sounds like its coming from the rear of the motor as well.)

I sea-foamed the motor. (Then drove it hard)
I seafoamed the tranny back in Aug. of last year. The hot level is at 1/4" or so over the cross hatches on the dipstick and runs red and clear. (idk why but the level doesn't change much when its cold...) My dipstick doesnt have a "hot" or "cold" level. Just some crosshatches an inch and 1/2 above the bottom tip.



Ok so you think it could be one of the three sensors you mentioned. Im guessin that one of those would throw a code? The noise is like I mentioned, sounds like a steam locomotive a chshhhh sound thats in time with the motor. (it sounds like its coming from the rear of the motor as well.)

I was seafoaming the motor. Sprayed the stiff right into the intake. Tranny has had seafoam in it for the past 7 months or so.

I will get a video of what the truck does later this evening, as well as the codes it throws.

Its not that I think those one of those sensor is bad. I just listed them as a possibility due to them being the primary source or input for the pcm's decision on when to shift and unlock the converter.
 

01yellerCobra

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Re: Truck lurches forward and stalls when going into forward gear. Sticky TC? Or wors

What about a TPS going out? If it's giving bad signals the ECU won't know what's going on.

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Expe101

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Its not that I think those one of those sensor is bad. I just listed them as a possibility due to them being the primary source or input for the pcm's decision on when to shift and unlock the converter.

Yeah, I know what you mean. Here are my codes. Working on uploading a video.

EDIT: I know its long but here it is. http://www.youtube.com/watch?v=KYY9syf3APs

working on the metal sounds.
 

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Expe101

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kmh1596

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Don't think seafoam is made to even go in the trans at all.. Let alone be driven in there for months.. I'd guess it was damaged by that. Seafoam thins out the oil when it is in the crankcase, and is only meant to be in there short term. No transmission with any amount of miles can stand fluid that is too thin...
 

Jeff532003

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Don't think seafoam is made to even go in the trans at all.. Let alone be driven in there for months.. I'd guess it was damaged by that. Seafoam thins out the oil when it is in the crankcase, and is only meant to be in there short term. No transmission with any amount of miles can stand fluid that is too thin...

Seafoam makes "seafoam trans tune" I was assuming and hoping he meant that. I have no clue though if its meant to stay in or not. I avoid transmission additives like the plague.
 

tsgrpr97

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Re: Truck lurches forward and stalls when going into forward gear. Sticky TC? Or wors

Have not heard of a torque converter not wanting to unlock.

I've had a tranny with the T/C stuck in lock up. Exact same symptoms. Had to replace the solenoid that controlled lockup. That was a GM. I'm not familiar with the specifics of the tranny that's mated to the 4.6, but I would assume Fords lockup works similarly

I know you don't want to hear take it to a shop, but before its damaged - take it to a good independant guy. He could at least give you a professional opinion. Then go from there.


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Expe101

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Seafoam makes "seafoam trans tune" I was assuming and hoping he meant that. I have no clue though if its meant to stay in or not. I avoid transmission additives like the plague.

Yes, it's the trans tune. I was using the seafoam intake cleaner on my motor. Come to find out it MIGHT be my TPS. (The TPS was already dirty.) That seafoam stuff might have gunked it up, causing a high idle. (900RPM instead of 600-700RPM) Im pretty sure the TC is an 800RPM stall TC. I'm going to eliminate that potential issue this morning. I should have used MAP sensor cleaner, not the oily seafoam stuff.

The seafoam trans tune really helped with my slipping and hard shifting issue. Didn't really want to flush it, kinda going with the rumor that the junk in there is holding the tranny together... (It hasn't been flushed in the last 150,000 miles.) heck, it's probably never been flushed...
 
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Expe101

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I've had a tranny with the T/C stuck in lock up. Exact same symptoms. Had to replace the solenoid that controlled lockup. That was a GM. I'm not familiar with the specifics of the tranny that's mated to the 4.6, but I would assume Fords lockup works similarly

I know you don't want to hear take it to a shop, but before its damaged - take it to a good independant guy. He could at least give you a professional opinion. Then go from there.


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Yeah, if a new or clean TPS sensor doesn't fix the issue then I'm taking it to get some troubleshooting done on the transmissions electrical stuff.
 

toms89

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I've had a tranny with the T/C stuck in lock up. Exact same symptoms. Had to replace the solenoid that controlled lockup. That was a GM. I'm not familiar with the specifics of the tranny that's mated to the 4.6, but I would assume Fords lockup works similarly

I know you don't want to hear take it to a shop, but before its damaged - take it to a good independant guy. He could at least give you a professional opinion. Then go from there.


Sent from my DROID4 using Tapatalk 2


That makes sense!

Based on viewing you video it appears that both shift points and lockup are effected but that could be explained if the converter is not releasing when its commanded. Find it a bit odd no codes where set though as the pcm monitors converter lockup.

I would try a new tps sensor and if that doesnt take car of it, I agree take it to an expert as more potential damage to the tranny may result if not taken care of quickly!!
 
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Jeff532003

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Yes, it's the trans tune. I was using the seafoam intake cleaner on my motor. Come to find out it MIGHT be my TPS. (The TPS was already dirty.) That seafoam stuff might have gunked it up, causing a high idle. (900RPM instead of 600-700RPM) Im pretty sure the TC is an 800RPM stall TC. I'm going to eliminate that potential issue this morning. I should have used MAP sensor cleaner, not the oily seafoam stuff.

The seafoam trans tune really helped with my slipping and hard shifting issue. Didn't really want to flush it, kinda going with the rumor that the junk in there is holding the tranny together... (It hasn't been flushed in the last 150,000 miles.) heck, it's probably never been flushed...

Two suggestions here for future reference.
First, when using seafoam as a top engine cleaner it's best to introduce it to the system through a vacuum line not the main intake for reasons you have stated. Don't want to fry a sensor or gunk one up. On our engines the brake booster line is perfect. Just take it off and let it slowly suck in the seafoam. A third of a can is enough. Don't want to cook an o2 sensor. Did that on a Hyundai once.

Second is "flushing" as in using a machine to change the fluid and adding in cleaner probably isn't the best idea but taking off the pan and changing the filter and draining the converter would probably do you wonders. Fresh fluid will not mess anything in a transmission up.
 
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Expe101

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Ok so finally reporting back here. Replaced the TPS and the IAC and that did nothing. A buddy of mine at Advance said he had the same issue and replaced the TC solenoid and the shifter solenoid. (Inside the tranny) so I did so and am in the process of putting it back together. I have one small problem. Literally as I was taking the pan off a plastic piece fell from the tranny into the pan. (See pic below.) I can find where that piece goes. I didn't see where it came off, just that (I think) it came from the passengers side of the tranny. Anyone know what this part is called and where it goes? Thanks!
 

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Expe101

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Just throw it away... Bad engineering design :) It's the dipstick plug during build.

:head3:

Are you serious!? That's the only hole that looked like it would go in but I didn't know HOW. Ok, if you ain't trollin, I'll chuck it. :)
 

kmh1596

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Just throw it away... Bad engineering design :) It's the dipstick plug during build.

:head3:

THIS...

Just did a new trans pan gasket and fluid last week, and my plug was in there. They just punch it through during assembly.

Let us know how it works!
 

tsgrpr97

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Re: Truck lurches forward and stalls when going into forward gear. Sticky TC? Or wors

Check if the torque converter has a drain plug, and if it does drain that too.

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