How bad... is this trans leak.

[MadMac]

Looks like a transmission leak... any inital thoughts?

Purchased my first '97 7.3L -95K miles. I've had it a month, took it on its first extended road trip - 500 miles round trip, 2/3rds mountain freeway, 1/3rd flat freeway - run somewhat hard, but not abuse - with 2000 lbs of shell and tools in the bed. 225 miles through return leg, stopped to get something to eat. Returning after 20 mins, there is a small puddle the size of my palm collecting under the front of the trans.

Finger test clearly shows nice clean tranny fluid, one drip per 5 to 10 seconds, and its only warm - not hot. No oil or fuel, and condensation is in a different puddle. Visual inspection - the fluid appears to be seeping down the sides of the flywheel/Torque converter access cover to collect at the valley point. Temps/Pressures normal, no slipping - so for a variety of reasons I drove it home. Morning inspection showed a similar sized stain on the cardboard I'd put on it. Guessing two tablespoons max. Multiple autotrans dip stick tests (running, cold, warm) indicate half way between min and max. It has since been "in-town" driven +5 times - without any additional leaking. Photo looks like its been cleaned up, which doesn't make me happy - but the time to whine about that is past.

So, I'm left thinking:

a) leak is coming from above the cover.
b) prep for sale maint could have over filled the trans fluid (is there a vent tube?)
c) transmission has to get really warmed up to leak...
d) something else is quite wrong, or will be...

Any thoughts, gut reactions, any simple tests - what do you think this is? Including when to have a Transmission Pro have a look - and any you know of in the Greater Sacramento Area...

 

[CharlesG]

I would start with the input shaft seal. It's a common leak point, usually shows up when the trans is warm.

 

[Jesus Freak]

If you ever tow reeaaaalllly hard, you can blow your front seal out and it will leak like the dickens right then. But after it cools off there will be no leak or a leak like you discribed, and it'll appear to be fine. And then one day you'll NEED to pull a load up a hill or something and it'll blow out and leak like crazy again, because the seal is forever compromised and not trust worthy. As long as everything works like normal on your tranny, you're fine to pull it and just replace the front seal.
That's one senerio the other is: it's a 30 yr old piece of rubber that wants attention. In which case, you can still just change the seal.

 

[gnathv]

That’s my thought.

 

[MadMac]

Quick update, its been a couple of weeks. Ran it again for four 250 mile runs in addition to in-town short 2 to 10m runs. It stopped leaking, when the dip stick level dropped below “full” mark. I’m still not happy, as now I’ll forever doubt the front seal… Thanks everyone.

 

[Jesus Freak]

I promise, beyond a shadow of doubt, the next time you REALLY tow it will leak. You'll be fine for casual driving, even the long runs. Be careful.

 

[greenskeeper]

flex plate original? Might be a good reason to replace that and then do the transmission seal. Neither is terribly difficult as I've removed the E4OD and transfer case without a lift on my 97

 

[MadMac]

Agree with the sentiment - "its gonna leak"... taking the optimist view of things... it has already caused me to check for leaks at every stop, and to check fluid levels when fueling up. Fear made me be a better owner I guess.

Not certain how I'll make the decision to replace the trans - likely it will be involuntarily obvious at the time - but given the general effort to get to any of the parts, I'm likely to go direct to a bulletproof version...

Thx gentlemen.

 

[MadMac]

Update - plus one year. its happened twice since, and this third time yesterday - I think I have the pattern. 1) Long five hour drive, bed full of tools, 6K in trailer+cargo. 2) it sits for 10-20 minutes on arrival. 3) it is used to "walk" a trailer into a tight spot 100ft down a narrow driveway. Which means alternating between reverse and drive - 10 to 20 times. Having put almost 15K miles on it since this post last year - if there were a problem with drive... the transmission would have drained all its ATF and expired long ago.

So I conclude - it leaks like a sieve when its hot and put into reverse. Question is - what to do about it. Photo of the street is included... Nothing where it was parked prior to going into reverse. There are another - two - long streaks down the driveway, and two foot wide puddles. Drove it to the shop this morning - and absolutely nothing came out of it.

@Jesus Freak noted it would happen again under load, and get worse - and here is the evidence! Only thing we didn't know then - is that it happens when in reverse. Most previous responses were - front seal.

At this point I figure my choices are - have the front seal done and see what happens, or just replace it. I'd appreciate any opinions before I dive in on this one. Thank you everyone.

 

[Jesus Freak]

That's some fine scientific study. But replacing the front seal should do it. The only hitch in the giddy up will be if the torque converter has any maring on the shaft but I really doubt it would.

 

[trackspeeder]

Replace the pump seal with a Viton seal. The stock seal is known for expanding when hot.

 

[MadMac]

That's some fine scientific study. But replacing the front seal should do it. The only hitch in the giddy up will be if the torque converter has any maring on the shaft but I really doubt it would.

Turns out to be much more than the front seal. The pump was nearly done, several retainers were badly worn (one broken in half), clutches scored, torque converter wasn’t always engaging correctly, it was done. The good news is - it didn’t strand me hours from home which it most certainly would have done on the next trip.

First problem showed at ~98K miles, failed at 108K miles. Wanted a Monster Trans, but the four to five week time line made that impossible. Upgraded most of the internals. Rebuilt by Scottys A1 Trans in Sacramento in four days.

Thanks to everyone for the help and advice.