Mystery transmission leak...

Here's one for ya: 94 4l60e leaks only sometimes??

Every once in a while I'll find a t-shirt size puddle of trans fluid under the car.
Can't really see any drips, looks like it's Coming from everywhere, obviously I'll clean and check, but the funny thing is I'll drive it and then it's all dry. And no leak.
Happens on flat parking, not inclines.
Previous owner said it's the rear tailshaft seal, I'm not buying it so much, it seems more forward than that.
Trans lines look like garbage and they are moist. But I think if it was them it would leak a constant amount.
Gonna replace all of it, but for now just wanna figure it out so I can keep and eye on it.

Here's an example: took the car to work yesterday. 25 minute ride, highway speeds 65, down to 45 on the main routes, and some idling at about 10 sets of lights. Pull into the parking lot and get under the car not a spec of trans fluid. I go punch in and work about 2 hrs and since it's a holiday and no bosses are in I decide to go outside and fix a loose exhaust pipe. Still no fluid. About 6 hrs into the shift I run to the 711 for some food, it's a 3 min ride maybe. 40mph, 1 set of lights. Grab what I need and return to work. Total running time maybe 10 min. About 4 hrs later when it starts getting a little light out I go out again and there a huge friggen puddle under the car.. Wipe it Down but no idea.
7 am I punch out and head home. I take the pike to 395 ALL highway 65mph-70mph.
Get home look under the car while running with a jack.... NOTHING! pan is damp but not a single drip
WTF is going on ?????

Not over filling it are you?
When you see the puddles are you adding fluid?

No I haven't added any fluid (even after it lost some)
It's Not a massive amount coming out, just a massive puddle (if that makes sense)
Big puddle, but thin layer. Not losing enough fluid to notice any slipping or anything.

So front pump seal or gasket, pan, lines, harness connector, vent or tailshaft.

Do you have the dust shield over the convertor?
If THAT's in place the pump seal or gasket should show without spraying everywhere.
Sometimes it'll drain real good, but on inclines etc, not so much

How confident are you in the way you secured the lines?

Very strange the way its showing...

Time to travel with some cardboard & a couple of rocks?

PS: I HATE drips...have plenty, just HATE them

Dust shield is in place, leak is not that far up. I'd say if I had to pinpoint exact location it's originating from I'd say pan/where tailshaft bolts to trans/cooler lines enter the case area.

I never touched the lines in this car. I just noticed the bottom line looks wet from the radiator all the way to under the cradle. Could be oil could be trans. I wanna wash the engine down this week with degreaser to actually be able to see what's what, it has like a 1/2" of crud everywhere. I'm deleting A/C hopefully Monday. So that will clear up some room. And I'd like to get her up on jack stands so I can actually comfortably get under there and look at everything.

My friend's 75 Lesabre does the the same thing, but only after it has been sitting for a couple weeks without running. Found it to be the dip stick grommet is dried out, how running it stops it from leaking is beyond me though.

When its running all the fluid isnt sitting in the pan

Thats a low pressure area

Good thinking Dave! I'll investigate that little bastard too!

Just drove it to work no leaks before starting the car, and no leak when I arrived. I'm gonna go out in a few hours and check.

*
Check for a clogged vent tube.

Maybe a small spider crawled in there and made it's nest, and later abandoned the tube leaving a blockage.

Only small residual pressures deliver ATF to the cooler/s.

While driving, less oil is sitting in the reservoir pan. It mostly drains back down after you park the car.

Line pressures are only found inside the unit, and are not likely to be the cause of your leaks.

When ATF fluid is heated and cooled, it expands and contracts, did you notice the ambient temperatures when these puddling events occurred?

With a blocked vent, expanding or contracting ATF will be pumped or syphoned in pathways not intended by the Turbo Hydramatic engineers.

This will also happen to engines, rear axle housings and transfer cases, and will usually pump fluid past the shaft seals when there is no functional venting.

The transmission vent tube is a small short nylon hose located up high where the bell extension transitions out of the gear-case section of the transmission unitized housing.

It exits the case and lays flat against the transmission pointing back and down, not sticking up straight out at 90 degrees.

Trans fluid can leak out from several places and travel around the pan flange and drop off at the opposite corner.

Also check the gear selector shaft seal, & as mentioned - the dip stick tube grommet, speedo housing, governor cover, 4-way electrical plug body entry point, pressure tap plugs, pump body o-ring and front main seal, tail housing o-ring, tail shaft bushing & seal.

If the tail shaft bushing is worn, (common enough) then the angle of the slip yoke can vary depending on the parked "phase" of the drive shaft, and that can cause the slip yoke to "cock" at an angle that opens up the bottom of the tail seal.

As far as temps go it's only been happening the past week. But previous owner said it was happening before I bought it,
This morning leaving work it seemed like it was going to slip, not quite there, but like it was very close. I pulled over and added a quart and she went back to normal.

Leaving work: no puddles
After getting home: no puddles
Left in the afternoon: no puddles
Returned back home: no puddles


I opted to take the fleetwood into work tonight to be sure I wouldn't break down (I'm also fighting rearranging my engine compartment to fit all the stuff and run Anthony's trailer fenders, almost lost the computer this AM)

It would be one thing if it was constantly doing it, I'd just wipe it and see where new fluid came from, but this is really sporadic and random. And the spots seem to keep changing.

I'm more interested in the "why" than the where at this point.

Ironfistdog wrote:

I'm more interested in the "why" than the where at this point.

The "why" will be the "where".

If you want to do the very least, then just add some of that "automagicical" transmission additive, Lubegard #61910, and drive around a bit. It actually does work.

Shine a flashlight down on the dip stick tube grommet to see if it is dislodged, folded over or cracked.

And then jack up one corner, support the car in neutral and wiggle some transmission appendages while checking for looseness, including your transmission's tail-shaft slip-yoke.

Also, if you gently put a little compressed air down the open dip-stick pipe, you should hear air only blowing out of only your nylon vent tube.

I got 2 days off starting today. I'll try all that you recommend.
Id rather not add anything that will gum up or in any way negatively influence the transmission's life.
If you think it will help AND not hurt down the line then I'll add some lubeguard.

I'm more or less worried I'll be without the car, we are currently down to 1 vehicle (since the caddy is gonna be useless in winter)
So I really can't afford to have the car laid up any more than a day or so. I gonna start with the small stuff and work up to the front pump seal (which I assume is the hardest job of all the things mentioned)

As an old school machinist, I generally don't go in for magic potions, elixers or any one of a vast array of snake oils being hawked at every corner you turn.

I ran over a very large, heavy duffel bag at highway speed when I was trapped between cars, it emerged from under the truck in front of me, my car was/is very low, so I hit it real HARD.

My exit was up next, just a few miles down, but the area is very hilly, nevertheless I attempted to get safely off the roadway, friday afternoon rush behavior was the order of the day.

Turns out that the aluminum pan and support was smashed dumping all the ATF out, and I continued to drive until it would not move, but I did make it safely away from the insanity of the highway.

Towed the car the rest of the way, put it up on stands, assessed the damages, bought a guaranteed good spare unit, but decided to just try replacing the broken parts as a first attempt.

The parts went on, straightened out the fuel pump and filter support, etc., etc., added new ATF, and subsequently the car had very bad shifting issues and and much worse clutch slipping than before.

I was not surprised though, because the car already had 240,000 miles on it and increasingly slipped while carrying a full load of people, if also accelerating hard up hills, so I deduced that the unit was indeed finally lunchmeat.

Talked to a good buddy that professionally builds race transmissions and he suggested I try this additive before I bail on the unit, since the spare was still an unproven boneyard pick.

Added this bottle and now today, the same fluid (w/additive) is still in there five years running now, and the unit slips much less than it did before it hit the duffel bag.

BTW, the duffel bag turned out to be a huge black Bull Mastiff that had snuck out of his fenced yard and on to the highway for the last time, I'm just glad I wasn't driving the vehicle that caused it's demise.

After that, I put the same treatment in my slipping 84 Olds that still has that pathetic little 200-4R in it, and also in my 88 LS Brougham's 700-R4.

Machine-De-Zine wrote:

As an old school machinist, I generally don't go in for magic potions, elixers or any one of a vast array of snake oils being hawked at every corner you turn.

I ran over a very large, heavy duffel bag at highway speed when I was trapped between cars, it emerged from under the truck in front of me, my car was/is very low, so I hit it real HARD.

My exit was up next, just a few miles down, but the area is very hilly, nevertheless I attempted to get safely off the roadway, friday afternoon rush behavior was the order of the day.

Turns out that the aluminum pan and support was smashed dumping all the ATF out, and I continued to drive until it would not move, but I did make it safely away from the insanity of the highway.

Towed the car the rest of the way, put it up on stands, assessed the damages, bought a guaranteed good spare unit, but decided to just try replacing the broken parts as a first attempt.

The parts went on, straightened out the fuel pump and filter support, etc., etc., added new ATF, and subsequently the car had very bad shifting issues and and much worse clutch slipping than before.

I was not surprised though, because the car already had 240,000 miles on it and increasingly slipped while carrying a full load of people, if also accelerating hard up hills, so I deduced that the unit was indeed finally lunchmeat.

Talked to a good buddy that professionally builds race transmissions and he suggested I try this additive before I bail on the unit, since the spare was still an unproven boneyard pick.

Added this bottle and now today, the same fluid (w/additive) is still in there five years running now, and the unit slips much less than it did before it hit the duffel bag.

BTW, the duffel bag turned out to be a huge black Bull Mastiff that had snuck out of his fenced yard and on to the highway for the last time, I'm just glad I wasn't driving the vehicle that caused it's demise.

After that, I put the same treatment in my slipping 84 Olds that still has that pathetic little 200-4R in it, and also in my 88 LS Brougham's 700-R4.

That must be a hell of a product then. I'm surprised it worked that well, maybe it should be in my future with the cougar.

Anyway... moment of silence for the pooch

It's Baaaaaaaaaaaack!

Made a nice spot in the garage, BUT now that I have a garage I can actually look at stuff, it's definitely coming from the VENT TUBE! but still only sporadically. Any ideas what makes fluid come out the vent? Not overfilled. Not overheating to my knowledge,

Clogged cooler lines?

"27. All fluid pumped out through the vent tube: Plugged cooler line. Flush the transmission cooler and cooler lines. Also could be overfiled transmission."

http://www.impalassforum.com/vBulletin/showthread.php?t=227226

Replace your trans lines, flush your coolers and don't overfill (Might want to add a 9C1 cooler)
Oh yea, remove your trans inspection cover! It will run cooler.

9C1 cooler different then that used on an Impala?

To lazy to go to the b-body illustration book...

I think they're the same.