Wet tranny pan
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Junior User
Joined: Jul 2008
Posts: 75
Likes: 0
From: Dallas TEXAS!!!
Wet tranny pan
'78 F100 Explorer: 302 V8, auto
After diagnosing an oil leak and fixing it (oil sending unit, thanks all for the help), and diagnosing a fuel leak and fixing it (fuel pump was shot, again- thanks for the help), I was rather upset to find more "mystery fluid" under my truck. Slid under her and found that the transmission pan was wet and the mystery fluid appears to be ATF.
So where's a good place to start looking for problems? Engine-to-transmission connection? A leak in the pan gasket? I can't see anything obvious, so I'm kind of fishing for a few trouble spots to check. I don't think it's further back (like to the drive shaft) since the whole pan is covered in droplets, not just the rear, so I've kind of narrowed it down some.
Is this anything a freshman home mechanic should be tackling? Any "gotchas" to be aware of?
Thanks all!
After diagnosing an oil leak and fixing it (oil sending unit, thanks all for the help), and diagnosing a fuel leak and fixing it (fuel pump was shot, again- thanks for the help), I was rather upset to find more "mystery fluid" under my truck. Slid under her and found that the transmission pan was wet and the mystery fluid appears to be ATF.
So where's a good place to start looking for problems? Engine-to-transmission connection? A leak in the pan gasket? I can't see anything obvious, so I'm kind of fishing for a few trouble spots to check. I don't think it's further back (like to the drive shaft) since the whole pan is covered in droplets, not just the rear, so I've kind of narrowed it down some.
Is this anything a freshman home mechanic should be tackling? Any "gotchas" to be aware of?
Thanks all!
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Common places that cause leaks in this area include the pan gasket and shift linkage seal. You've got to remember that old trucks leak and rattle; that's the nature of an old truck. You can drive yourself crazy trying to run after every little detail. The important thing is that the fluid is reasonably topped off all the time. If it's leaking so much that you're ruining your driveway and you're low on fluid all the time, then I'd look at those 2 places first. If it's just a little seepage that keeps the pan greasy, that's fairly common after 30 years.
Posting Guru
Joined: Mar 2006
Posts: 1,118
Likes: 0
From: Williamson, NY
The first thing to do is totally clean off all the oil that is visible and then take your truck for a short ride and then see if you can find the leak by evidence of some fresh oil. The places fmc400 stated our the usual culprits, but you can't rule out the tranny pump seal yet.
Elder User
Joined: Dec 2007
Posts: 739
Likes: 1
Spray clean it down with brake-clean or the like. Get it nice and rinsed off and dry.
Now this sounds odd? But this works. Sprinkle baby powder on the transmission. Around the pan..linkage...etc... Start the engine..and shift through all gears. Do this several times. Now crawl back under and see if the white baby powder has any 'wet' looks to it. That'll be where your leak is.
If you want to get 'fancy'? You can use UV oil die made for engines and transmissions. From there all you do is use a UV light source--you'll see a nice glow where the leak is.
**now before anyone gives me crap about baby powder? This is how Ford had some of the shops check for porous housings on some Escorts and Lynx cars. It was a huge pain--Drop the transmission---Clean it like 'new'---Dry...Coat the snot out of the entire thing with baby powder---Reinstall---Drive----Drop and inspect the powder. They did a recall for this issue, as they had major leaks and hosed transmissions.
S-
Now this sounds odd? But this works. Sprinkle baby powder on the transmission. Around the pan..linkage...etc... Start the engine..and shift through all gears. Do this several times. Now crawl back under and see if the white baby powder has any 'wet' looks to it. That'll be where your leak is.
If you want to get 'fancy'? You can use UV oil die made for engines and transmissions. From there all you do is use a UV light source--you'll see a nice glow where the leak is.
**now before anyone gives me crap about baby powder? This is how Ford had some of the shops check for porous housings on some Escorts and Lynx cars. It was a huge pain--Drop the transmission---Clean it like 'new'---Dry...Coat the snot out of the entire thing with baby powder---Reinstall---Drive----Drop and inspect the powder. They did a recall for this issue, as they had major leaks and hosed transmissions.
S-
Elder User
Joined: Dec 2007
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S-
Elder User
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From: Northern Minnesota
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Laughing Gas
Joined: Aug 2007
Posts: 1,107
Likes: 32
From: Spokane, WA
Ewwwww...is it possible to burn the retina in my mind's eye? Not what one would call pleasant imagery.
As for the leaky tranny, the cardboard test is a good way to start...let gravity see if it can show it to you first. Then the baby powder, then the drive. If I had to guess, I'd be willing to bet the pan gasket has been crushed, as people have a really bad habit of overtorquing those pan bolts. The other side of that is that the gasket is ok, but the pan itself could be warped along the flange after having been overtorqued for years. Each bolt hole could have just a slight difference in plane than the rest of the flange, and it won't allow for the pan to seat fully. I've seen this on a few pans, and the only solution is to either have the patience of a saint and try to flatten the flange without damaging it, or to get a new pan.
Anyway, that's another potential theory.
As for the leaky tranny, the cardboard test is a good way to start...let gravity see if it can show it to you first. Then the baby powder, then the drive. If I had to guess, I'd be willing to bet the pan gasket has been crushed, as people have a really bad habit of overtorquing those pan bolts. The other side of that is that the gasket is ok, but the pan itself could be warped along the flange after having been overtorqued for years. Each bolt hole could have just a slight difference in plane than the rest of the flange, and it won't allow for the pan to seat fully. I've seen this on a few pans, and the only solution is to either have the patience of a saint and try to flatten the flange without damaging it, or to get a new pan.
Anyway, that's another potential theory.
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Elder User
Joined: Apr 2003
Posts: 502
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LOL The many uses of baby powder!
Hopefully its just your trans pan gasket. Try just tightening the bolts up-ya never know! Keep in mind, small bolts, aluminum, and sheetmetal- crushing cork-so use very little torq. or do the recommended manual torq. spec.
Easy to change, kinda, just messy-and besides it probably needs new atf anyways.
There are rubber gaskets available too.
Hopefully its just your trans pan gasket. Try just tightening the bolts up-ya never know! Keep in mind, small bolts, aluminum, and sheetmetal- crushing cork-so use very little torq. or do the recommended manual torq. spec.
Easy to change, kinda, just messy-and besides it probably needs new atf anyways.
There are rubber gaskets available too.
