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The Band, not the Disease!
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Hey guys, on my 97 mark VIII, it feels like 3rd is slipping. All shifts are quick and firm, just when under light acceleration or cruising, in third gear, it will raise rpms about 100 - 200 and then be normal, then raise again, in pretty quick succession. Car has 160k miles and as far as I know, the trans is original. Should I drain the pan and TC, clean out the VB and update the accumulators and fill it with fresh Merc V, or just put that 100 bucks into a new trans? Under moderate and heavy acceleration, there is no "slipping"... it's just under light throttle and cruising it feels like this. Any advice?
 

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Sounds like your pressure regulator valve needs to be replaced before you burn the direct clutch up. The sonnax valve doesn't wear nearly as bad as the stock one and you can also get their upgraded valve that comes with a spring that add's a slight pressure increase. It isn't much but it doesn't take much to make a big difference.
Alan
 

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I don't know. That almost sounds to me like the computer is commanding the converter to slip in an odd fashion. I see this a lot when there is something going on that causes the load the computer is seeing to be off. IE, a dirty MAF or an issue with the TPS or any of the sensors that the computer is looking at for this.

Could be wrong though.

Darrin
 

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The Band, not the Disease!
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Discussion Starter #4
Darren: I will definetly check the MAF and TPS, since it's free and easy.

Dirty: Where is this said regulator at? Would I be able to get to it by dropping the pan and VB?
 

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You don't have anything that you can datalog it with do you? That is the best way. Then you know if it's from a command or a problem.

Darrin
 

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Hell, you are here in Indiana. Bring me that car. LOL

Alan can sell you a Sonnax valve if you need it. I don't offer those, but I can install it for you.

Darrin
 

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The Band, not the Disease!
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Discussion Starter #7
I have to drop the VB anyway, but the pressure reg is in the VB right? I think it's in the side and it just pushes in with springs, correct? Thanks for the offer, though =) Yes I do have a snapon scanner that i use.
 

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I think it is the PR valve because it is happening at low load, when the pressure gets high enough the valve will stroke, but I can almost guarantee unless it has been changed the stock valve is toast. I'm seeing 15,000 mile units already showing considerable wear. The EPC is prone to the same issues. I haven't seen a late EPC all worn out yet. The new bracket(04+) seems to work better. I don't think it will work on the old epc solenoid however.
Alan
 

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Just out of curiosity did you try and diagnose it? I would love to see what the computer is seeing and asking for at the point where this happens.

You have to forgive me, I have just always been the type who tries to figure out what is wrong before I start throwing parts at it. It's just a thing. In my experience I have found that you can throw parts at it and some parts might even make the symptom better while leaving the real problem to burn you in the butt with a surprise failure.

Not saying that I know what the problem is, just saying that I always think it's best to at least try to figure out what the problem is before you 'fix' it.

Darrin

Darrin
 

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The Band, not the Disease!
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Discussion Starter #12
I datalogged all the info, and i compared it and nothing seemed out of the ordinary, Fuel trim, TPS, MAF.. all seemed OK. I do like to diagnose the problems first, I was just asking how much they were, and if they happened to be relatively inexpensive, I would just put them in because Im going to be doing the jmod and such to the mark anyway. :D
 

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I was hoping you might look at the TCC duty cycle to see what it is doing right then as well.

The parts are inexpensive enough for sure and no harm doing stuff while you are in there. I am just trying to guide you to some things you can do to try and eliminate some stuff up front. I am sure that all of us have been there to how much it really sucks to get it all together and drive it and have the same or worse issue.

But, you are correct, if you are in there anyway...

Darrin
 

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The Band, not the Disease!
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Discussion Starter #14
I don't think my scan tool said anything about the tcc solenoid, it's a pretty limited tool. Main stuff is MAF voltage, O2's, Fuel Trim, engine load and such. I cant unlock or lock the TC in any way with the scan tool. However the TC is locking / unlocking normally in OD gear. Any thoughts?
 

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My thoughts are still what I was thinking initially. I think the computer is commanding the torque converter to slip because of something that it's seeing and that is what you are feeling or hearing.

How many miles are on your fluid anyway? Also, is this something that you are feeling more, hearing more or that you just happened to notice and are watching now?

Darrin
 

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The Band, not the Disease!
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Discussion Starter #16
I bought the car with 130k on the clock, and its at 160 now.. so the trans fluid is unknown! :( Im the only one that can tell it's there.. maybe im just being paranoid. lol
 

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I've actually been noticing this same exact problem on my 96 4.6 cougar. Only in 3rd gear the rpms raise a little and then crop down a few times has I accelerator. Fluid has 40K-45K on it so I need to replace it and I'll deffinetly have to take a look at what the TCC duty cycle. I'm doubting it is the MAF on my car as I replaced it a week or two ago and even with the old MAF the car was acting similarly in 3rd.

EDIT The car doesn't have MERCON V in it and isn't torque converter flare supposedly one of the things upgrading to V helps with?
 

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Mine has the same thing as well. Switches fine in all gears, but after it's warmed up going to 3rd gear unler light load it feels like it 'surges' till it gets a little deeper in teh gear(maybe around 1800+rpm). Under heavier load it's not as noticable. I have no way of data logging and have been eyeballing the Jmod. I already replaced the fluid with merconV and a filter change about 2K miles ago. My bird has almost 156K on it and I can gaurentee that valve has never been replaced(my mother was the original owner and had all the repairs done at Ford which I have the reciepts and did not find one for that)

Dirty Dog, how much is the pressure valve? I saw the vid you posted and you make it look easy
 

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Can anyone give me the proper ranges for torque converter line pressure? They seem to be very low on my car.

If any could also supply the normal range for EPC pressure that too would be greatly appreciated.
 

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Never mind I've found them here they are if others are interested

AODE

Note: All pressure tap locations are clearly MARKED right on the case on AODE's & 4R70W's.

Main Line Pressure

* In P/N, OD, D/2, 1 @ Idle Hot - 50 to 75 psi
* In P/N, OD, D/2, 1 @ Stall Hot - 160 to 210 psi
* In Reverse @ Idle Hot - 80 to 120 psi
* In Reverse @ Stall Hot - 220 to 280 psi

EPC Pressure

* In P/N, Rev., OD, D/2, 1 @ Idle Hot - 0 to 9 psi psi
* In P/N, Rev., OD, D/2, 1 @ Stall Hot - 83 to 93 psi
 
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