The tranny dip stick tube leaks at the o-ring on my 727. I have tried several things and not had much success. What have you done to fix these things? I have had these leaks on other trannies and didn't have much luck fixing them either.

Tips and tricks would really be appreciated.

get the O ring from a dealership, or a transmission shop. Most of the generic ones at the hardware store are not the right thickness and will leak.

I fixed one by jacking the car up at an angle so I could pull the tube w/o dumping fluid, dry/degrease the area REALLY well with brake cleaner and lacquer thinner then reinstall the tube with a new o-ring AND a smear of RTV at the mating area and o-ring. Reinstall, complete with the securing bolt (to prevent further movement of the tube, and let cure for 24 hours before leveling car.
It worked.

Also--they sell many different o-rings--use the thickest one you can, and the RTV helps here to, acting as a lube.

I had a tough one that defied several attempts at sealing it & I finally pulled the pan/dipstick/dipstick tube & cleaned the hole in the case/end of tube thoroughly w brakekleen/replaced the O ring/plenty of RTV esp on the top side/lesser amt below the O ring/let situp overnight. Prob solved. Originally in my attempts I did not get it squeaky clean which prevented the RTV from sticking to the metal and the trans fluid would wick up past it so I had to pull the pan to get it ALL clean down there

use some of the Mopar black ATF/RTV from the dealer with a new o-ring



drop pan,clean with brake clean,install with ATF/RTV and let cure over night

I change the filter,adjust bands,install newer style gasket from the dealer,torque the pan bolts and let sit over night before refilling it

I also look at any of the other seals that may or may not be leaking and evaluate the need to replace any at that time.I also check the rear servo pivit pin at rear of the case/tail housing(that leak can make you think its the dip tube or something else if over looked)

most times I do the TPV seal,gear selector shaft seal,fill tube o-ring,pan gasket,rear seal,adjust bands all at one time if I plan it right

factory o-ring the best and install with a small coat of trans oil...best installed dry....worked for me

A common problem with them is that when people remove the tubes they get aggressive and crack the tube at the O-ring groove. Most often not noticable and they don't see it. After a couple or-rings and tries they get tired and RTV the tube into place. OK until you need to remove the tube.

Make sure the Tube isn't bent or cracked and get a good O-ring. IF it still leaks you can either slather it with RTV or some people weld the end of a GM tube in place of the Mopar tube and use the GM seal. If it's a small block you can use a Tube from a Magnum engine shortened as needed. The Magnums already use the GM seal.

if it doesn't seat squarely the o ring will seep
you'll get a smooth fit at the upper trans mount when it's correct at the bottom
as others note,rtv helps

Some years do not have the bolt on the dipstick near the oring area.

They only use a bracket to the back of the bellhousing.

I have fixed this problem a couple of times by using a new O ring and loosen the bracket bolt. Put a screwdriver in the tube and give it a couple of light taps to seat the tube a little deeper in the trans.

But,
more than once I found the sector shaft seal was leaking and the fluid ran to the corner near the dipstick and dripped throwing me off track..Had to change the sector shaft seal..

Another thing to check is actually make sure that it is seated all the way down. Its hard to get it pushed all the way in when the push angle is not centered over the hole and the tube is curved (it hard to get a good straight push).

When I was younger I would push them in but it would stop at the oring and I though I had it seated, I had perpetually leaky trans. One time when I was trying to get it to stop I got the right angle on it and it slipped further in. Problem solved!

Just something to check.

If you not opposed to a non-stock appearing dipstick the locking ones sold by Mancini have a better design seal similar to what is used on current mopar trans dipsticks... Also basically the design used by BM for years... It doesn't leak... I have in the past bought a new dipstick & cut the bottom couple inches off & cut a like amount off the original dipstick tube then welded the new section on the old tube to keep the original look... Lotta work but it stops the leak & keeps it looking stock...

http://chucker54.stores.yahoo.net/man727diptub.html

And the seal is the one used on late GM trans
Ron
Hey how's the Dart comin'?

Hey Ron, how's it goin'?

The Dart is in limbo right now. The body man called just before he was scheduled to start on it and said he has to have open heart surgery. I am still trying to find an acceptable plan B.

I guess I will just graft a GM bottom to the tube in the Dart. I did that to the Cuda and it worked out good. No leaks. I just thought I would see if there were any other cures outside of using GM parts on the thing.

Thanks!