Transmission Fluid Seepage

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On my 98 Expedition with 4R100 tranny, I have been chasing a fluid seepage issue. The truck is parked nose down on a slight decline of the driveway. I have done a drain, filter change and refill with Max Life Synthetic (Same as I have been running for years), Also drained torque converter.
Fluid appeared to be leaking around front pan bolts after the fluid change, so I removed pan, cleaned all surfaces on pan and transmission very well, put on new factory gasket (dry), torqued bolts to spec (10-11 ft/lbs). Refilled and it still leaks on bolt heads.
This picture is after 12 hours after wiping everything dry
[Linked Image]

Any ideas of cause and solution?
I am thinking of dropping the pan again and using Hylomar between gasket and tranny and between gasket and pan surfaces, but that is a last resort. I don't see why it should need any additional sealant, other than the new gasket...besides the fact that it leaks
 
Is the mating surface gouged anywhere? Are you torquing in the pattern listed in the service manual? Does Ford require new pan bolts each time? I know some cars do.

Maybe the gasket isn't seating properly when you go to mount the pan. A light coating of adhesive spray b/w the pan & gasket will help everything stay in place.
 
No gouges, torqued in proper sequence, gasket is lined up properly, I used a flashlight to make sure gasket holes lined up with bolt holes after installing 2 bolts to hold it in place.
I tried to avoid any additional adhesives, since the previous service by someone else had used some adhesive that turned into a soft spongy mess, obviously not compatible with ATF. I thought that is why it leaked before, so that is why I did a remove and replace
 
How is the condition of the surface? Is it perfect?

Verify that the pan is not warped. Do you have a straight edge?
 
Ford you say? Not boiling out of the vent is it? Otherwise get a straight edge and check for flatness or do like suggested and ditch the gasket and use RTV, fat bead and make sure it doesn't migrate into the pan.
 
If someone in the past overtightened the bolts, the pan lip will be dented upward around each bolt. That will not seal.

10 ft-lb seems really tight for a transmission pan bolt. Are you sure the spec isn't in-lb?
 
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Originally Posted by mk378
If someone in the past overtightened the bolts, the pan lip will be dented upward around each bolt. That will not seal.

10 ft-lb seems really tight for a transmission pan bolt. Are you sure the spec isn't in-lb?


This is possible, I did notice as I was scraping old material off with razor blade, that it would get hung up on some edges around some of the bolt holes, but didn't think much of that since the gasket is quite thick, that it would take up that small intolerance at the bolt hole.
If this might be the issue, what is the solution....seems like we are talking thousandths of an inch...I really don't see this being the issue, given how thick the gasket is, even around the entire perimeter of the hole on both sides of a metal gasket, but I am willing to consider anything at this point.
 
Perhaps for $42.00 from the dealer, a new pan might be a good thing to consider at this point. The bottom of the transmission surface was perfect. As I stated, the previous servicer used some material in addition to the factory gasket, maybe that is why.
 
Originally Posted by Fitz98
Originally Posted by mk378
If someone in the past overtightened the bolts, the pan lip will be dented upward around each bolt. That will not seal.

10 ft-lb seems really tight for a transmission pan bolt. Are you sure the spec isn't in-lb?


This is possible, I did notice as I was scraping old material off with razor blade, that it would get hung up on some edges around some of the bolt holes, but didn't think much of that since the gasket is quite thick, that it would take up that small intolerance at the bolt hole.
If this might be the issue, what is the solution....seems like we are talking thousandths of an inch...I really don't see this being the issue, given how thick the gasket is, even around the entire perimeter of the hole on both sides of a metal gasket, but I am willing to consider anything at this point.


With scratches, gouges, dented flange, a metal gasket hasn't got a chance. Maybe they make a rubber or cork gasket, but RTV would fill in the gaps and minor variations of the mating surfaces much better.
 
It's a metal cored gasket for shape, but it has a thick silicone/rubber-like (don't know what material) beaded seal on both sides of the metal core.
not a metal gasket
 
Originally Posted by MasterSolenoid
Here's some advise I received on Trans Gaskets.
https://www.bobistheoilguy.com/foru...on-pan-gasket-silicon-or-not#Post4850598

I had good success with:
1) Only Gasket / NO Sealant (but gasket dressing is OK in my book)
2) Make sure Pan is perfectly flat / and around bolt holes
3) Clean both surfaces
4) Use torque wrench and stagger the tightening
5) Retorque a day later


This is very important. Three other things:

a) I dress both surfaces with a file to eliminate any burrs, find high/low spots, and promote adhesion.
b) I dress with Permatex Aviation #3; it will not be difficult to remove later like FIPG
c) I re-torque not only a day later, but after at least one full duty cycle of getting to temp/cooling.

I hate using FIPG as it is such a paint to remove if you ever take the pan off again. And I have no problems with leaks using the above technique
 
The new pan I got does have small sharp ridges around each bolt hole on the gasket side. I imagine it is a stamped piece and that would be expected.
I like the idea of filing these ridges flat, but was concerned how filing grooves/scratches would affect the seal. On top of that, this new pan appears as if it may be galvanized? It is steel/magnetic, but silver in color, so if it has some sort of rust resistant coating or treatment, will I introduce a potential area for rust problems wherever scratched?
[Linked Image]
 
Did you check the pan flange for flatness around the bolt holes? I would bet they need a tapping with a ball peen hammer and a new gasket, NO RTV!
 
OP,

Before installing the 'new' Pan, did you RETORQUE the bolts after noticing it was leaking ?
Use proper torque (not more) and retighten in stagger pattern.
For 'my' Pan, I found the sequence on the web and numbered the Bolt Holes with a magic-marker.

Your 'new' Pan :
If you do any filling or hammering, be CAREFUL you don't make it worse.
Right now, it's in the condition Ford would install it as.

Reread my 'post' from when I changed my gasket.
https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4850598/2

If not too late, clean off the drips and RETORQUE.

If your torqueing to 10-11 Ft Lbs, get yourself a TW with In Lbs
10-11 Ft Lbs (=) 120-132 In Lbs.
You may get a better feel (if using an adjustable clicker type)
Go around at 40 In Lbs, then at 90, then at 125.

Let us know how you do.
 
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I also was wondering if the old pan was " puckered " around the bolt holes . I have seen people hammering them out flat , on youtube .

I would be tempted to take the new pan back to Ford and to buy a new , thicker ( and maybe deeper ) pan with a drain hole / plug . Maybe cast / forged / stamped aluminum ?

I often will use the non-hardening Permatex ( #2 , I think ) and " glue " the gasket to the removable part . This helps keep the gasket from " moving around " and is easier to scrape off , with the removable part on your work bench . If you ever have to do this again .

Remember , if you use sealant , too much can " squish " out and " gum up " the inner workings of the transmission , engine , diff , gear box , etc. .

Best of luck , :)

Wyr
God bless
 
Thanks for all the advice. I am disappointed in the new pan. The intention was to get a new OEM to eliminate the pan from my troubleshooting, but it has less than a perfect surface. I either have to file it flat or return it and get an aftermarket pan. Are aftermarket any better? Perhaps something with a machined gasket surface rather than stamped?
 
Originally Posted by Fitz98
Thanks for all the advice. I am disappointed in the new pan. The intention was to get a new OEM to eliminate the pan from my troubleshooting, but it has less than a perfect surface. I either have to file it flat or return it and get an aftermarket pan. Are aftermarket any better? Perhaps something with a machined gasket surface rather than stamped?


Mag Hytec
 
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