Ford 6600 transmission leak

tbgord

New User
Good evening all,

Just bought a 1981 Ford 6600 for the farm and it has a small leak that's got me wondering. Dead center on the bottom of the
transmission is what looks like an cotter pin stuck in a hole. The mechanic that delivered it said it could be a vent hole, but I've
never seen one on the bottom before. It was leaking clean oil a week ago but is now leaking milky murky oil.

Is this a factory hole with a missing plug or screw? Is this something someone else has done to it?

And as the tractor was only lightly used for the past 4 years and it was stored over winter and I'm starting to make it work, would
the milky oil be old sludge being forced out of unused lines/ports?
cvphoto23381.jpg
 

Its a vent hole with the cotter pin in it to prevent it from plugging up... in the clutch area....Its job is to keep that area drained of any fluids or the clutch will fail

any leakage would be from either the transmission front seal, or the engine rear seal.

milky usually means the transmission fluild is leaking...... as you hope your engine oil is not milky or you have serious engine problems. Milky transmission fluid is common due to water egress through the shift levers.

sometimes a bit of watery fluid drips a bit after a power wash but rare.

could it also be a freeze plug on the back of the engine leaking and mixing with some residual oil??
 
Sotxbill correctly described the purpose of the hole. If the fluid is clear, then it's tranny fluid. First thing I'd do is replace the 1/8" and 1/4" pipe nipples going through the RH side of the case that feeds the dual power. More than once I've seen those crack and leak internally. It would be a cheap and easy fix.
 
So if it's to keep the clutch dry then getting a few tablespoons of oil each time I shut it off would be
a sign of a seal leak. Too much to be normal? And definitely too much to let into a hay field.
 
So if it's to keep the clutch dry then getting a few tablespoons of oil each time I shut it off would be
a sign of a seal leak. Too much to be normal? And definitely too much to let into a hay field.

Does it drip constantly while running, or just when you shut it down? Have you checked the transmission fluid level to see how much you're losing over a period of time, both with the tractor parked and while running it?
 
I haven't checked it too thoroughly yet, but I know it only loses a few tablespoons of oil after I shut it down. I haven't found the
dipstick for the transmission yet, but found the fill port beside the shifters. I looked pretty well for an hour for the dipstick. Found
the one for the engine and rear diff tho. But even that one doesn't make sense. Would love to find an online owners manual for it.
 
I doubt it. On my 7000, the cable froze up. Still available from NH last I checked, but $$$. Some aftermarket company need to add that part.
 

Another likely place for the leak is the transmission input shaft seal, or the PTO shaft seal. The amount of leak that you describe can probably wait until after your season to repair. You may also find that once you work the tractor for a few hours that the milkiness goes away as the fluid heats up. Be aware of how your clutch is working because a leaking seal can put oil onto your clutch.
 
A 6600 should have a common reservoir for the transmission, hydraulics, and rear end. The dipstick should be on the left side, near your heel, as you sit on the tractor. It will have a long tube and be accessed from the rear, if it has a cab.
 
Yep. Seen that one and its full and clear. Looked in the filler port by the shifters and saw the rails and gears coated with oil but nothing pooling in the bottom from the little I could see.
 
So I worked the tractor for a few hours yesterday
and it did leak a small dribble of oil from the vent
hole but neither engine or tranny oil seemed down
any amount. I can't find a cross section picture of
the transmission to see how the set up is configured
to keep the oil out of that area or how much oil leak
is expected.
 
(quoted from post at 06:10:25 05/20/19) So I worked the tractor for a few hours yesterday
and it did leak a small dribble of oil from the vent
hole but neither engine or tranny oil seemed down
any amount. I can't find a cross section picture of
the transmission to see how the set up is configured
to keep the oil out of that area or how much oil leak
is expected.

tbgord, it is pretty much universal amongst vehicles of all sorts that the transmission case has 6 sides and holes at front and rear for the shafts to go through, with seals at the shafts to hold the oil in the case.
 

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