Transmission Leak only after sitting in driveway?

[Lazerskull]

Here is a mystery for you all.
(1997 XLT SOHC 4.0)

Took my Explorer on a long road trip about 700 - 1000 miles round trip. Multiple days, didn't
drive more than 1-150 miles without long breaks (6 - 36 hrs. each). This is Northern California
in the summer, during the firestorm near Ukiah. Weather was nice and moderate. Started in
Sacramento, went to Petaluma for a night, then up to Eureka with a lot of stops on the way for
swimming, etc... Camped @ Big Lagoon near Orick, great trip!

Another disclosure: did a little beach driving in Samoa, had to deflate the tires, ran beautifully in
the sand. Just drove out to a nice place to enjoy the afternoon, not too heavy. Ran fine. Was a
little bumpy at first, so might have jarred something loose then... but this happened in the
middle of my trip... and three days after didn't notice any problems...

So I go back home through Willits, it's serious fire country at this point, lots of smoke
everywhere. People on pins and needles. But as far as the Explorer ran, she ran and sounded
surprisingly smooth.

Get home, make a mental note to change the oil etc when I can.

So I store the vehicle go back to work and my usual stuff. About a week or so passes by and I
figure I better start it up. I think I gave it an oil change. Can't remember.

Well I go to warm it up and drive around the block and suddenly white smoke is coming out
from underneath. I've had this before, and looked at the Catalytic Converters and sure enough...
it's tranny fluid burning on top, dripping down from the transmission pan.

I go back home and tighten up the pan and clean up as much as I can. Drive it again, this time
I drive it longer and on the freeway so as to burn off the oil.

Well it is still leaking out. So I take it home store it again and it's leaking through the bolts.

So of course it's gotta be the gasket right?

But this is my question. If it was the gasket. Why didn't leak when I was driving it all around the
country for a week. Why did it wait until I got home and was sitting in the driveway for another
week then it decides to leak? Were my guardian angels watching over me while I was on the road?

So I take it to "Mr. Transmission" in Roseville, CA.

I had them do a synthetic transmission oil change / filter and gasket / and the rear main seal by the drive shaft for 320$.

So again. Why the delayed leakage? Doesn't make sense to me. I am taking it on all these
trips and it doesn't leak. But it has done this before. It leaks after a drive and after sitting in the driveway...


Here are some photos. Pardon the ski racks in summer. They're like the Christmas lights on
that one house in the neighborhood, by the time I wanna take them off it's the season for
leaving them on again... :/

 

[koda2000]

When the engine is running trans fluid is being continuously pumped through the transmission. This keeps the amount of fluid in the trans pan lower than when the engine is turned off. With the engine off most of the fluid in the trans returns to the trans pan, putting the fluid level at/above the level of the trans pan gasket.

If the pan is warped (due to over-tightening the retaining bolts or it hitting something) the gasket can leak, or the gasket may just be leaking. The trans fluid level is also higher when the fluid is hot, that's why there are COLD and a HOT markings on the trans dipstick.

 

[Lazerskull]

So it could theoretically just be a warped pan. Is that something the average joe can do. Can I salvage the fluid. Because if these guys are charging me 320$ for new pan gasket and rear seal... and it still leaks, I wanna try and do the pan myself and save the new fluid if possible.

Thank you. I feel educated now.

 

[koda2000]

I suppose you could buy a new $12-$15 fluid transfer pump and suck out the trans fluid through the dipstick tube into a clean container. You'll probably be able to suck out around 4+ quarts of ATF (at $6-$8 a qt that would save you around $30). Wait until the vehicle sits overnight to allow as much fluid as possible to drain into the trans pan before pumping it out.

After sucking the fluid out of the trans, dropping the trans pan is straight forward (just remove the bolts). There will still be some fluid in the pan and the valve body will drip, so have something to catch it in and try to keep the pan level while removing.

Once the pan is off and cleaned up check it for pan straightness with a suitable straight edge and a flashlight. If it's warped you'll probably need to replace it. If you haven't changed your trans filter in a while, you might as well install a new one, which will often come with a new gasket. I use WIX trans filters and they come with a new gasket. I changed one of mine recently, followed the directions to coat the gasket with some grease before installing it and have had zero leakage/seepage. You can purchase the gasket separately.

If your trans tail-shaft seal is also leaking, you need to remove the driveshaft from the rear diff in order to remove the shaft and replace the seal. Do this before putting the fluid back in the trans. A new tail-shaft seal is probably around $10. You'll need a 12 point socket (or box wrench) to remove the 4 driveshaft bolts, IIRC they're 12mm.

EDIT: I should add the the transmission dipstick tube seals into the transmission with an O-ring. That is another source of possible trans fluid leaks after setting. Worth checking.

 

[Lazerskull]

Hi Koda. Thanks for all your help. I received my Explorer back from the mechanic (do not go to them, Mr. Transmission
in Roseville / I will explain why). I let it sit a few days. Then I cleaned up the bottom so all the oil was off there.
Then I took it for a nice lap around the town, about 10 miles round trip, city streets and highway speeds up to 75 mph.

So then I gave a look underneath to check the work of the mechanics and I found this.

All of the other bolts are dry. This one is wet.

So I cleaned it off and drove it around again. Just to be 100% sure.

And same thing. All the bolts are dry. This one is wet.

So I called the mechanic. I told him about it. He said it's possible the pan is warped.
But if it was warped, they should have seen it. He said it could just be a loose bolt.
He admitted, and I have it recorded, that they don't use torque wrenches.
So he admitted, "they just do the best they can. Sometimes they miss one or leave it
loose."


He also said if the pan was warped, it wouldn't be covered under warrant, so I
would have to pay for additional work. Excuse me? If it is warped, then they are
at fault for not seeing it!

Someone told me I can wrap something around the bolt and re-tighten it?
And that might solve the issue?


I went ahead and torqued all the bolts to 12 foot pounds. Which I heard someplace
is the official torque? Is that right?

They all seemed right about there, so kudos to the mechanics at "Mr. Transmission"
for getting it as close as they did on the feel. Still, it seems ludicrous that a commercial
shop doesn't even have a torque wrench. I am guessing this is the policy of the
corporate overlords, so as to expedite the service time (while still charging the full service
time) as they can avoid that "annoying" step of having to look up torque specs.


Needless to say I won't be handing them my rig back. No way, no how.

The jack is just in case of an earthquake.

 

[974X4BLACKSPORT]

Happens to everyone sometimes (one wet bolt), LOL
I do all my own work too, I never use a torque wrench on the trans pan bolts, I always snug them real good "incrementally" in the attempt to NOT over tighten them.
12 ft/lbs sounds like alot for a trans. pan bolt.

 

[koda2000]

I have been wrenching on cars/trucks for nearly 60 years and I don't use a torque wrench on things like pan bolts or other non-critical things. I always use a torque wrench on suspension parts, most bearings, wheel and brake hardware. I have a good feel for how tight to make stuff and I would assume most experienced mechanics do too. I do 99% of my own repairs and 100% of my maintenance as I don't trust most mechanics and shops to do things correctly plus the cost savings of doing things myself is huge.

For your one wet pan bolt you could try removing the bolt, cleaning/drying the bolt/bolt hole and putting some RTV on the bolt's threads before reinstalling it. It might help, it might not as I don't think any of the bolt holes are thru bolts. You may just have a slight warp in your pan.

 

[donalds]

This brings me back to the dent in my trans pan

Wasn't bad to repair at all I reused my fluid but had some on standby just in case didn't spill any fluid Trans pan dent ok or not

Anyway here's a link to my post lots of pictures it may help