Transmission leak on 727

[7DCUDA383A]

Good info here guys about other leak sources. I would question the shop's capability if it was leaking from any place but the pan. Rebuild means changing out all the seals, O-rings and gaskets. Hopefully they didn't take short cuts and it's leaking in one of the other places folks here have mentioned.

They did not rebuild the trans just addressed the leaks which was mostly gaskets and seals of the engine and trtans , I see alot of issues on this thread so I hope they are close to narrowing it down , hopefully . I know they used a couple different gaskets , not sure which ones , I think they are doing the best they can not being a classic car shop , mopar shop , especially the way the car was put together . I find out Monday if they finally figured it out .

 

[493mike]

I have found the best way to install the sector shaft seal is to draw it into its bore with a 5/8" cap screw, nut, and 2 flat washers.
Mike

 

[AUSTA]

Sometimes the leak is coming from further up runs down unto the gasket the around & it appears the gasket is leaking . i had a persistent leak it turns out the new nuetral switch was not crimped properly on the end & the oring was leaking seen a few do that now no quality control

 

[pschlosser]

I'm sure those guys know what they're doing. Some of those shops have all kinds of documents on the wall, showing off how smart they are.

 

[Bret Schneider]

Make sure the bolts are the correct length. The four bolt holes at the front of the 727 transmission are not through holes so if one of those bolts is slightly long it could bottom out in the hole before the pan is properly torqued.
If the leak is coming from around the bolts you might want to try a sealing washer like this.

Sealing Washer: For Screw Size M8, Metal Bonded Washer, Steel, Cadmium Plated, Buna-N Seal​

Item 55DV17
Mfr. Model 9500-08MM

Not sure why this it says this link to the washers doesn't work... works for me

Whoops, we couldn't find that.

 

[Ronbo73]

My 727 does not leak from the trans pan. I am using a deep aluminum pan with a silicone/rubber re-useable gasket (mr gasket). The aluminum pan has a thicker pan flange that is flat and will not dimple like a steel pan. Also have them make sure the transmission mating surface is clean with no deep scratches, dents or nicks etc.

Look into the aluminum pan, I don't think you will be disappointed. I think B&M makes one.

 

[GiantRobo]

You could also try the OEM A518 gasket. It works great on 727s, even with sheet metal pans: 2464324AC. Don't get an aftermarket version. The OEM Mopar is hard plastic with shaped "orings" to seal unevenness.

 

[7DCUDA383A]

You could also try the OEM A518 gasket. It works great on 727s, even with sheet metal pans: 2464324AC. Don't get an aftermarket version. The OEM Mopar is hard plastic with shaped "orings" to seal unevenness.

View attachment 133316

Is this the gasket that the dodge dealers carry

 

[Spyder]

Mine was good for many many years and then one day I backed out of the garage to see what looked like a gallon of red on the floor. The neutral safety switch decided to leak. Fairly quick, cheap, and easy and somewhat messy fix. Haven't had any other problems with this one just yet, other than getting the kickdown and linkage set up just right.

 

[aussiemark]

Check the kickdown when your looking at the shift shaft seal I think it has an O ring from memory.

 

[Ronbo73]

You could also try the OEM A518 gasket. It works great on 727s, even with sheet metal pans: 2464324AC. Don't get an aftermarket version. The OEM Mopar is hard plastic with shaped "orings" to seal unevenness.

View attachment 133316

Hello GiantRobo, quick question. Do you remember what you torqued the transmission pan bolts to? What I have seen online is 105 in/lbs.

 

[Spyder]

I used my stubby ratchet and held it close to the head and tightened as tight as I could with one hand. No science but it worked for me.

 

[Xcudame]

I used to use a short 1/4" drive rachet myself for years. Then I splurged and got one of those adjustable screwdriver torque wrenches.

 

[moparleo]

Pardon Our Interruption...

 

[aussiemark]

I used my stubby ratchet and held it close to the head and tightened as tight as I could with one hand. No science but it worked for me.

As you get older your wrist becomes a natural muscle memory torque wrench that never needs calibration.

 

[Horse72Chall]

I've just had a similar leak in my A727. You would drive it and then park it up, and there would be no trans fluid leaks at all. Would be the same for a couple of days parked up. Then I walked into the shed a couple of days later and found around 2.5 litres of trans fluid on the floor.
Did a bit of investigation and found that the tranny wouldn't leak for a day or 2, while most of the fluid was trapped up in the converter. After a day or 2, the vacuum inside the converter would let go and drain all the fluid back into the pan and lift the fluid level up high enough to pour out of the old and brittle selector shaft seal...
Changed out the selector shaft seal and problem solved. No more leaks...
I also added the B&M deep aluminum sump/pan and filter extension to increase the trans fluid volume. Just watch the ground clearance with the B&M pan though, as it is now the closest part of the under-body to the road...