Dipstick pops out

[68383GTS]

My transmission dipstick always pops a good part of the way out when driving.Fairly stock 383,727 TCI trans,and 410 gear. Any fixes for this?

 

[Willyrd]

Sounds like you're lacking in the crankcase ventilation department

 

[68383GTS]

Sounds like you're lacking in the crankcase ventilation department

So the transmission would vent through the engine crankcase? Don't think thats even possible, or am I wrong?

 

[Willyrd]

So the transmission would vent through the engine crankcase? Don't think thats even possible, or am I wrong?

Sorry I misread your post, I thought you said engine dipstick. Have you made sure you haven't over filled the trans?

 

[rustycowll69]

I believe the vent for the trans is in the bellhousing, at the top of the front pump housing cover. I imagine that a small amount of venting is through the filler neck/dipstick tube, too.

 

[Dana67Dart]

So the transmission would vent through the engine crankcase? Don't think thats even possible, or am I wrong?

you are correct not possible. When I read your post the first time I assumed Engine. Then I re read your post...

My transmission dipstick

Simple answer is rubber grommet / gasket is no longer large enough dia to keep side tension on the tube.

OR

the trans vent is clogged

OR

both

You might not have oil coming out the filler but air pressure might be and pushing the dip stick out.

Final thought...

is the dipstick hitting the bottom of the trans pan? check with long straight rod and compare to dip stick length.

 

[Dana67Dart]

Not sure if this is correct but came up in a google search

 

[Dicer]

727 vent is located behind the converter on the front pump......try a new dipstick "O" ring....
Mopar W0133-1668962

 

[Dana67Dart]

General question for the 727 gurus. If one was to put very low pressure air (like a hose and your lungs) into the dipstick tube would that prove the vent is open if it did not pressurize?

 

[rustycowll69]

General question for the 727 gurus. If one was to put very low pressure air (like a hose and your lungs) into the dipstick tube would that prove the vent is open if it did not pressurize?

I don't know for sure about that, but if so, maybe you could rig up a cork plug with a tire valve and use a bicycle tire pump with a gauge to check it.
I wonder if the front pump gasket is idiot proof, or if one could inadvertently put the gasket in wrong and cover up the vent passage.

 

[68383GTS]

I didn"t think there was a vent Thanks

 

[Dana67Dart]

I didn"t think there was a vent Thanks

See the bottom of post 6 from the FSM

 

[Dana67Dart]

maybe you could rig up a cork plug with a tire valve and use a bicycle tire pump with a gauge to check it

My concern would be blowing out a gasket with too much presdure.

 

[rustycowll69]

My concern would be blowing out a gasket with too much presdure.

if it's working at all, I don't think you'll be able to pump it up more than a few pounds, and it will bleed back down in just a few seconds.

 

[brian6pac]

There is a plate that bolts to the front pump that is a cover for the vent

 

[AJ/FormS]

I've had that happen with too much fluid in the trans. You can tell it's overfilled by the foamy evidence on the stick, but you'll have to be quick to catch it. Plus the fluid come waaay up the stick.
I have bench-tested to 3psi with no problems; your results may vary. You will have to use shop air tho, cuz with the main vent open, it pisses out pretty fast. On the bench I can put my thumb on the port.

 

[44067gtdart]

I've had that happen with too much fluid in the trans. You can tell it's overfilled by the foamy evidence on the stick, but you'll have to be quick to catch it. Plus the fluid come waaay up the stick.
I have bench-tested to 3psi with no problems; your results may vary. You will have to use shop air tho, cuz with the main vent open, it pisses out pretty fast. On the bench I can put my thumb on the port.

I have had similar problems in the past.. I am just curious, how far is the dipstick supposed to stick out from the bottom of the filler tube when it is completely inserted?

 

[Jadaharabi]

Not sure if this is correct but came up in a google search
View attachment 1715226859

.
I believe that is where you put the vent on a racing transmission. After you plug the front vent hole to keep oil from coming out at the pump.

 

[70aarcuda]

ATI Replacement Locking Transmission Dipstick Handles 973081

 

[AJ/FormS]

I have had similar problems in the past.. I am just curious, how far is the dipstick supposed to stick out from the bottom of the filler tube when it is completely inserted?

I'm gonna guess about an inch to an inch and a quarter. It's been a few years, so forgive me if that is wrong.
EDIT
No that's not right, see below

 

[Inertia]

I don't know for sure about that, but if so, maybe you could rig up a cork plug with a tire valve and use a bicycle tire pump with a gauge to check it.
I wonder if the front pump gasket is idiot proof, or if one could inadvertently put the gasket in wrong and cover up the vent passage.

Nope, - a lotta other things wouldn't work if you did.

 

[12many]

I have had similar problems in the past.. I am just curious, how far is the dipstick supposed to stick out from the bottom of the filler tube when it is completely inserted?

On the original matching tube and dipstick from my 67 727, the dipstick just barely protrudes from the end of the tube, maybe a 1/4"

 

[44067gtdart]

On the original matching tube and dipstick from my 67 727, the dipstick just barely protrudes from the end of the tube, maybe a 1/4"

Ok.. Thanks.. That's what I had, but I wasn't sure if I had the correct dipstick.. I thought I may have been overfilling it.. An O ring should fix my leak.