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It amazes me the amount of knowledge here on these trans so I must ask a few questions. When I'm cruising down the road I have a terrible vibration through out the car. If I let off of the throttle it goes away until I accel. again.

From what I've read on here I might say it's the same problem many have. I did the flush, filter and merc V change but it did return after a few hundred miles but not as bad. I've heard that the J-mod may help and I'd like to do it anyway but not sure what to do on the 99 transmissions since parts were being corrected by Ford this yr.

My question is would I benefit from doing a trans filter/fluid change again( I thought there might still be old fluid in there) to get rid of the vibration/shudder or is it something else? What do I need to drill/change on the 99 trans to do the J mod? The cars got 160k on it and I have no idea what the previous owner did as of maintenace but the fluid was pretty clean the first time a flushed it.

Sorry for the long post. :confused:
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Is this happening in all gears, or only 3rd and 4th?

The J-mod won't cure torque converter shudder, if this is what you are experiencing. If the fluid and filter are new and you still have vibration, either the TC itself has gone bad or there's another cause to the vibration (motor mounts, trans mounts, misfire etc).
 

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I would also check the U-joints for not only slack, but also hard spots in the needle bearings. To check for hard spots, you will have to remove the driveshaft. I also agree with Brandon on checking all of your mounts. All 3 (L and R engine mounts and the transmission crossmember/mount) were busted in my 99GT and it had strange vibrations while cruising. Blew my mind that the whole trans mount on the 99-04 is the "crossmember."
 

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Discussion Starter #4
Is this happening in all gears, or only 3rd and 4th?

The J-mod won't cure torque converter shudder, if this is what you are experiencing. If the fluid and filter are new and you still have vibration, either the TC itself has gone bad or there's another cause to the vibration (motor mounts, trans mounts, misfire etc).
Yes its just 3rd and 4th. How do you tell if your mounts are shot, Ive got some movement on the drivers side but cant tell if its a normal amount or not when you rev it up.

I would also check the U-joints for not only slack, but also hard spots in the needle bearings. To check for hard spots, you will have to remove the driveshaft. I also agree with Brandon on checking all of your mounts. All 3 (L and R engine mounts and the transmission crossmember/mount) were busted in my 99GT and it had strange vibrations while cruising. Blew my mind that the whole trans mount on the 99-04 is the "crossmember."

I checked the u-joints for slop but didnt think about hard spots. I may just relace them anyway since its a cheap repair and Im sure down the road Ill have to anyway.
 

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i usually just wedge a BF prybar in their and start prying, they shouldn't move around very much if at all. the motor mounts will move a bit more since the engine torque. if you have an excessive amount of movement, or if the mount is completely broken like the trans mounts do sometimes, you'll know right away.

just make sure you not prying on anything delicate, or easily broken :)
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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If it's only in 3rd and 4th, then it could still very well be TC shudder (the converter only locks in 3rd and 4th in the stock tune). You can try with fresh fluid again, but if the converter itself is bad or if your trans is running hotter than it should be, fresh fluid will only be a band-aid fix.
 

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Discussion Starter #8
Ive also noticed its got a "whistle" in 1st gear but once it hits second it goes away. Overall the trans shifts fine for a stock trans thats why I thought it maybe something simple. Is there a way to rule out the converter other than replacing it?
 

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The whistle could be a vacuum leak that gets drowned out with road noise.

I'd verify no vacuum leaks first.

Whistling - someone who does transmissions (RobertP, DirtyD0g, et al) may chime in with how one can do that, but AFAIK, that's not a valid sound from a transmission.

RwP
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Whine is the pattern on the gears - all 4R70Ws have that in 1st gear. Whistle is the valve body. I recommend talking to Darrin @ BC Automotive if you decide you need transmission work.
 

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Discussion Starter #11
Does the valve body need replacement? With the whistle and shudder am I looking at have to replace the trans soon? What about the J-mod is there anything thats different than the write up Ive seen for the 99 and up? I did notice when I did my filter that it has the new accum. in the 1-2 so I assume the others are the newer ones as well.

On a side note I did check all my mounts and they look fine.
 

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Discussion Starter #12
The trans was a little low on fluid(about 1/2 qrt) and it seems to help it about 90%. Apparently I have a small leak at the rear seal and it drips on the h-pipe and burns off which is why I never noticed it. Im assuming the other 10% is probably wear?

Any ideas on the other questions I asked in the above post?
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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The trans shouldn't lose any fluid. It won't consume fluid when it wears like an engine will. If it's losing fluid, it's leaking somewhere. Common places are the front pump seal, rear seal and pan gasket. If all those places are dry then check the lines to the radiator cooler, then lastly the cooler itself.

As far as your other questions, I don't know enough to give a solid answer. You should already have the newer accumulator pistons though - if you do the j-mod it will be a matter of enlarging a few holes in the separator plate and possibly removing accumulator springs (depending on your needs).
 

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The 4R70W has inherent problems that will appear with age, reguardless of mileage (within reasoning) wether you agree or not is not of my concern, only to quash the idea that replacing a '94-97 trans with a newer version will be of benefit or worthyiness to the actual owner in question if the replacement unit is just as screwed as the original unit it is meant to replace, mechanical diode be dammened.

Kevin.
 

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These newer 4R70W transmissions are LIGHT YEARS ahead of the AOD; I hated the AOD and broke a few over the years, I LOVE the 4R70W!

They handle more abuse than ever before - more revs, more torque, and failure spots have been addressed throughout the years -

1994- New MLPS to address water getting in and ruining
1996, 1999, & 2001- Better valve bodies throughout the years
1996- New pan for slightly more, cooler, and not sucking air in the filter
1998- New high friction clutch material and mechanical diode
1999- Higher Pressure EPC solenoid
2004- New front pump
2006- Renamed 4R75W supposed to handle more torque and new pan
2007- Mechanical diode improved with more locking teeth

I haven't heard of the problem you mentioned before, but I'm no transmission expert either. I don't know if and when Ford put a better spiral ring because aftermarket has had them for years and I know of a few other tricks re-builders use to make for a stronger transmission.
 

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Nobody "Breaks" an AOD, they only burn them up because of what they don't know.


Kevin.
There's a couple of split ones at a local tranny shop that begs to disagree with you :diablo:

RwP
 

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Net ole buddy, nobody "Breaks" an AOD, they only burn them up because of what they don't know.


Kevin.
Oh, I wish I had pics. The last one I tore up had pieces of metal in the pan that looked like a bunch of 'Chicklets'!


There's a couple of split ones at a local tranny shop that begs to disagree with you :diablo:
RwP
I never split an AOD, but I once broke a Turbo 350 tranny in half with my Chevelle! :eek:
 

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You should have taken those pictures there, were those "Chicklets" in the pan clean metal or blued from heat colored? Clean metal would indicate a fatigue failure, possibly a internal shaft torrington bearing shedding itself into the gearset caused it? or did you lose the lube circut(radiator cooler/lines) and cause a failure of the pinion bearings of the gearset? both would be considered a internal contamination failure.

Now, if all those little chunks in the pan were black & blue from heat discoloration, I'd look for a lube circut flow problem/restriction that caused the heat to discolor those little chicks into chicklets, but what my money is riding on is that you never bothered to look past what you saw in the pan after draining. In which case you just don't know or cared to find out, you only know what you saw in the bottom of the pan.

But now that you've drilled a spacer plate, you consider yourself a drivetrain specialist.

Kevin.
 

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Why so hostile? Yes I too have see AOD's split, it can happen.
 
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