TCCoA Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter #1
96 Mark random Tranny Leak?
Hey guys, I'm new here so if I'm in the wrong area, let me know.

History: Ok, I've got a 96 Mark VIII with 110,000 miles. I've had it since it had 62,000. I changed the tranny fluid around 70,000 miles with synthetic. I've done about 1500 miles of heaving towing about a year ago, or around 105,000 miles.

Recently, I've noticed some tranny fluid puddling under the car, then it wouldn't move. I topped it off with more fluid and was able to get it back in my garage. But I don't see any leaking. I remember years ago having a C-4 in a Mustang do something similar, and with that it was blowing it out of a vent or something on top due to a bad pump.

Any common areas that are prone to leaking on the Marks that I should check? Do they have any types of "vents" that leak if the pump or whatever is going bad in the tranny?

If I have to drop the tranny...... I'll probably have it rebuilt or replaced. What's the best/ cost saving route (rebuild this one, or find something from a stang or pick-up, etc)? Would a shift kit with increased line pressure wake the tranny up a little?

One more..... I 've read about T-45 swaps.... I know it's rather involved... if I do most/ all work in house... what's a ballpark with the cost of the swap NOT including the T-45? Does the car have to be reflashed for a different idle speed? How much of an improvement in response and MPG would I expect to gain?
 

·
Registered
Joined
·
5,417 Posts
Could be the trans dipstick tube o-ring.
 

·
Premium Member
Joined
·
5,862 Posts
I'd check:
Pan gasket leaks.
Tranny lines are tight in case and not leaking.
Dipstick tube where it enters case.
Rear driveshaft seal.
Pull inspection cover in front, look for front seal leaks.
Look around MLPS (shifter) sensor on side.
Look around wire connector plug on other side.
Look where speed sensor plug on tailshaft is.
Trace tranny lines to radiator looking for splits, pinches, any damage.
Look where tranny lines screw into radiator tight and not leaking.

If the tranny is dirty, clean it real good with brake cleaner or pressure washer so you can see where fluid is leaking.

I am not aware of any "vents" the 4R70W tranny has. If you're just leaking fluid and that's the only problem, I'm not sure I'd worry about changing tranny. But if you want the toughest 4R70W transmission, the 5.4L pick-ups have toughest stock, but you have to re-pin the connector because 1998- use different pin-out than previous years.
 

·
Premium Member
Joined
·
649 Posts
I am not aware of any "vents" the 4R70W tranny has. .
Vent on top at Rear of Tranny before Extension Housing - Looks like a little gold hat - If you try & put more than 4-6 Qts in "empty" Tranny with front up on Car Ramps without a brief Motor start up to fill TC BELIEVE ME, you'll find out where the Vent is... it was a mess~!

If I have to drop the tranny...... I'll probably have it rebuilt or replaced. What's the best/ cost saving route (rebuild this one, or find something from a stang or pick-up, etc)? Would a shift kit with increased line pressure wake the tranny up a little?
At 139K Miles I just re-did my original 96 MK Tranny & VB myself w/help of these Boards - In the end I had about $2K in Project w/new D/Dog TC, Cooler, JMOD, ETC.. I'm VERY happy w/result - Majority here would say stay away from Shift Kits excepting JMOD & a few EPC & VB upgrades - I would do Overhaul & upgrades all at ONE time as truth is your 96 Tranny is on borrowed time.

One more..... I 've read about T-45 swaps.... I know it's rather involved... if I do most/ all work in house... what's a ballpark with the cost of the swap NOT including the T-45? Does the car have to be reflashed for a different idle speed? How much of an improvement in response and MPG would I expect to gain?
There are many Threads on this but I personally would not TOUCH that project unless I was installing newly Overhauled Motor~! - Yeah you'll be into PCM & I see no way our Gas Mileage could get any better than it already is (when we TRY for Gas Mileage that is) - IMO you'd be MUCH happier picking up a cheap Manual Mustang or TBIRD to play with & leave MK an Auto.
 

·
Registered
Joined
·
21 Posts
Discussion Starter #5
Yes yes! Thanks for the solid info guys! Yeah, those vent tubes/caps can puke out everywhere! I'll have to degrease everything and look at those areas listed and hopefully it's a simple corroded line or seal. How bad is the J-MOD to do? Is it like turning that screw in the AOD's to get more line pressure? Will it chirp the tires between 1-2 up shift? Would I pick up a couple tenths in the quarter or something? Can it actually get it to manually down shift every time, rather than when it feels like it?
 

·
Premium Member
Joined
·
649 Posts
Fave 4r70w sites:

Yes yes! Thanks for the solid info guys! Yeah, those vent tubes/caps can puke out everywhere! -POSSIBLE EXTENSION HOUSING GASKET LEAK TOO

I'll have to degrease everything and look at those areas listed and hopefully it's a simple corroded line or seal. How bad is the J-MOD to do? -MODERATE DEGREE OF DIFFICULTY

Is it like turning that screw in the AOD's to get more line pressure? -NO EPC SCREW TURNING ALLOWED~!

Will it chirp the tires between 1-2 up shift? -OPTIONAL

Would I pick up a couple tenths in the quarter or something? -YES

Can it actually get it to manually down shift every time, rather than when it feels like it? -YES
- More COMPLETE answers to your queries here:

http://www.tccoa.com/articles/tranny/transmission/index.shtml

http://www.p71interceptor.com/

http://www.dirtydogperformance.com/index.php

http://www.sonnax.com/index.php
 

·
Registered
Joined
·
21 Posts
Discussion Starter #8
Well, It was the dipstick tube. What a MPITA! Unless you wanna drop the exaust, it was next to impossible to reach the bolt for the tube's bracket, which is at the back of the head. I modified two 12" sawzall blades and bolted them together to make one 21" blade. Then, I carefully stuck the blade down through the engine compartment alongside the tube and cut the bracket holding the tube. The O2 sensor's wire loom is right there so gotta be careful. But it worked.I was able to remove the dipstick tube, replace the o-ring, then put the tube back. I modded a bracket to secure the tube in back place. It's temporary, but worked. It was easier than messing with the rusted bolts on the manifold holding the cats.
 

·
Premium Member
Joined
·
649 Posts
Dude even with the Crossover Pipe & the Starter out that Bolt retaining Dip Stick Tube to Tranny is a PITA - I literally dislocated my shoulder removing it - Either bi-metallic corrosion or loctite has that teeny thing IN THERE - Fab up some kinda solid bracket to retain it somewhere, preforated strapping might come in handy, you don't want something catastrophic going on~!
 

·
Registered
Joined
·
7 Posts
i didn't want to start a new thread since i saw it mentioned here. i have a leak around the mpls what is needed to fix this?
 

·
Premium Member
Joined
·
649 Posts
leak around the mpls

You really don't see many Posts about the Manual Lever Shaft Seal leaking so make DARN sure it's not the OSS Seal or a leak path down from the VENT above where you overfilled it while on car Ramps or something making you THINK it's Seal behind MLPS because that will be a BIGtime PITA - I think you'll have to drop Main VB to pull the Lever Shaft - & By the time you do that there are SEVERAL things you really ought to do while Main VB is down - & Then of course you can make a DAMN good case to just drop entire Tranny down & get the mid-life Overhaul it's gonna need ANY DAY NOW over with once & for all~!

Here's a Thread w/pic :

http://www.markviii.org/htdocs/dc/dcboard.php?az=show_topic&forum=21&topic_id=76572&mesg_id=76572&page=1
 

·
Registered
Joined
·
7 Posts
I'm not familiar with the term "oss seal" i've cleaned and degreesed the trans , changed the pan gasket
the only place i see fluid is on the drivers side by the mlps. nothing up higher than that.
 

·
Premium Member
Joined
·
649 Posts
Output Shaft Sensor is above MLPS - But if your clean & nothing dripping down then unfortunately that's BAD news...

So is it a 1994 survivor Tranny by some miracle or what? - Please 94_newbie,,, tell us more about yourself & your tranny...
 

·
Registered
Joined
·
7 Posts
i don't know much about the car. i just bought it on january 28th. i bought it for $500 because the heater core was leaking. it has an after market trans cooler on it and the fluid looked good before i flushed it. i found the leak after i filled to tran to the full cold mark . it looks to leak down to the bottom of the cold but no further.
 

·
Premium Member
Joined
·
649 Posts
Good info & damn good buy for $500 heater or no heater~! - I'd have to just watch this puppy for a while before biting any bullet$ - Keep CLOSE eye on ALL Fluids w/ ANY new purchase like this~!
 
1 - 15 of 15 Posts
Top