727 trans leak

-
George R

George R

Mopar Nutcase
Joined
Oct 29, 2007
Messages
2,646
Reaction score
69
Location
Trumbull, CT
Dumbass me overfilled (apparently) the trans last week. Didn't notice any leaks until Tuesday this week, when I saw trans fluid all over the garage floor. It seems to be coming out of the O ring at the fill tube. If I overfilled it, will it cause it to leak like this, or is the O ring just bad? I have never owned a car that didn't have a clutch.
I can't run the engine to check the fluid because I don't have a battery for the car. I can use my truck battery tomorrow, but if the trans is overfilled, will starting it to check the fluid do any damage?
Thanks for the help.

George
 
I have the same problem!!! Even before I filled my tranny with fluid, it started pissing out the filler tube hole there :violent1: What an awful design! Why couldn't they do a threaded deal like the speedo cable??? maybe a new O ring or two?
 
How far did you over fill it.If you over filled it by a quart I don't think it will hurt.The fill tube will leak if over filled and the O ring is old.I have done this myself.You may want to pull the tube out and replace the O ring.I have also used RTV before and it worked pretty good.
Jim
 
I would clean up the fluid, and get a drain pan. Remove the filler tube, with pan to catch excess, if any. Insert finger, stick, or whatever to make sure you have enough fluid in the tranny. You can then replace filler tube, (maybe with a new O-ring). Start car, and check fluid. Good luck. Howard
 
While on the subject.......

Ya know that lil plate in the tail housing? The one on the bottom? Held in with two Phillips screws? Covers a snap ring.

Anyone ever had one leak out of there before?
 
George R said:
Dumbass me overfilled (apparently) the trans last week. Didn't notice any leaks until Tuesday this week, when I saw trans fluid all over the garage floor. It seems to be coming out of the O ring at the fill tube. If I overfilled it, will it cause it to leak like this, or is the O ring just bad? I have never owned a car that didn't have a clutch.
I can't run the engine to check the fluid because I don't have a battery for the car. I can use my truck battery tomorrow, but if the trans is overfilled, will starting it to check the fluid do any damage?
Thanks for the help.

George
Click to expand...

Like everyone said, pull the fill tube and drain. Get a cheap turkey baster to suck out what you need. Don't forget that you check these 727's with the engine running and in neutral. Replace the O-Ring. It shouldn't leak even if somewhat overfilled.

68 Sedan said:
While on the subject.......

Ya know that lil plate in the tail housing? The one on the bottom? Held in with two Phillips screws? Covers a snap ring.

Anyone ever had one leak out of there before?
Click to expand...

I'ts a gasket IIRC. If you can get it completley dry with brake cleaner, you can just use RTV black but let it sit for 24 hours before cruising.
 
On the first "test drive" around the block, I noticed the trans slipping when I used reverse. It will take a while to engage once the shifter is placed in reverse, but it engages quickly when put in drive. That led me to believe, perhaps incorrectly, that the trans was low on fluid. There were no fluid leaks at the time. Rather than wait until the following day to check the fluid level, I simply poured another quart in. This is when the fluid started to leak out of the fill tube O ring. The O ring is old, no local parts store had one, and the O ring was not included in the trans filter kit I purchased like I thought ti would.
I'll see if I can get an accurate measurement from the dipstick later today.

Thanks for the ideas gentelmen. I appreciate the help.

George
 
Correct me if im wrong but when the trans is full isnt the o ring submerged.when in park the converter is no longer full and the valve body drains down right.
 
I usally just go to like ACE hardware.Go to the nut and bolt section.There is usally a selection of O rings there.
 
I'm not exactly one of the gentlemen here, but do know that overfilling a tranny can blow the pump seal and the converter seal too. The modulator (the little fuel filter/canister-looking thing -- for lack of a better explanation :-D -- with the colored stripe on it) controls the shifting itself.
 
I had a problem with my trans this week. It was the speedo o-ring, it was bad. Almost couldn't tell where it was leaking from. New o-ring problem gone.
 
CudaChick1968 said:
I'm not exactly one of the gentlemen here, but do know that overfilling a tranny can blow the pump seal and the converter seal too. The modulator (the little fuel filter/canister-looking thing -- for lack of a better explanation :-D -- with the colored stripe on it) controls the shifting itself.
Click to expand...

Yes, overfilling the trans can blow seals.

No Modulator on 727's, just Ferd and GM's :)

George,

Just get a O-ring kit from harbor freight. One of them will work (I used one on my last 727 rebuild). believe it or not, those O-rings are really high quality and you'll use the remaining O-rings on something else in the future. Use axle grease on the O-ring when you push the tube in to prevent shaving the ring. The grease will expand and condition the ring over time too.
 
I didn't mean to exclude you Leanna! Sorry about my lack of inclusion! LOL I value your opinion and experience very much, and thank you for participating in my thread.
I pulled the fill tube yesterday morning, and let the trans fluid drain down to the top of the trans case. I cleaned up the mess, and reinstalled the fill tube. I let the car run for a few minutes, and put the trans in drive. It wouldn't engage at all so I checked the fluid level. It was extremely low. I needed to add 2 quarts in order to get a reading on the dipstick that was close to full. There were no leaks at this time. The car shifts correctly again, and seems to engage reverse more quickly.
When I parked the car, I slid my drain pan under the trans to prevent another mess.
This Sunday am, I poked my head under there and I can see that the trans case is wet with fluid again, so I guess I need a new O ring seal. I'll check out a local store and see if they carry one that will fit.

Question..
How loose is the stock torque converter on this car? Its a stock 69 340/727 car with 323 gears. It feels to me like it takes more RPM than I feel it should to get the car rolling, but like I have said previously in this and other posts, not only am I new to Mopars (although I have owned Dodge trucks exclusively since 1986), I am new to automatic trans cars. I literally have owned close to 50 cars used as daily drivers over the last 28 years, and they all had manual transmissions, except for my 84 Buick Riveria Roadster that I drove over the summer of 1989.

Gentelman, and the few ladies present, thank you all for the help.

George
 
ramcharger said:
... No Modulator on 727's, just Ferd and GM's :)
quote]


Joe, it was a test. You passed! LOL (Actually, there is one -- part of the throttle body -- but it's not adjustable like those Ford and GM ones. Chalk me up for a blonde moment.)

I'll just stick with my powder coating and leave the tech advice to the gurus around here.
Click to expand...
 
You must log in or register to reply here.
-

Back
Top