Leak From Front of Transmission

[PiMaster]

Hi all,

Extreme novice to car repair here (i.e. have only done oil changes and swapping wheels on my cars at this point), just got my own place so I have the room to do work on my old Newport.

Transmission pan developed a gradual leak the past few months so I took it into a shop and long story short they couldn't stop the leaking after two tries. Got a new gasket myself and really cleaned up the pan before reinstalling and all seems well as far as that goes now.

I refilled the fluid, then a couple days later I noticed it was still about a pint or two low (measured in neutral while the car was warm), got under the car to check and was alarmed to see fluid coming out of the front of the transmission now where I have never had a leak before. The leak isn't horrible but if you wipe away the excess fluid new drips form almost immediately.

I have a service manual for 72 Chryslers but a lot of that goes over my head. This is probably a dumb question, but does anyone have any suggestions or pointers on what is causing the new leak? I attached a (not great) pic of the leak, you can see it's at the bottom of the front of the transmission, with the pan over to the left. I don't think I overfilled the transmission, maybe a half inch over the full line on the dipstick.

Thanks in advance!

 

[75LandYacht]

My uneducated guess is the Front trans seal. Since you now have New fluid running through the tranny, it may have broke loose some debris that was around that seal exposing a weak point in that seal. Hence a leak.

 

[C Body Bob]

Front pump seal has failed. This will happen to an older seal if the trans is run while low. Pull the trans out. Remove the torque converter. This is important ( I put a straight edge across converter hub to bell housing before removing & take a measurement to make sure it's fully splined on reinstall. It turns to fully ingage on splines. So put it back in the same distance) remove old seal & ONLY use a quality seal such as National. Yes it will cost more but will last years if properly installed. Also did I read right. It was a half inch overfill ? That too can cause the seal to fail.

 

[max1196]

Pump seal,Transmission needs to come out to fix this. Do the rear frost plugs of the engine (if this is a 318/360 equipped vehicle) at this same time.

 

[celticwarlock]

Looks like you're about to have a lot more grease on your hands than you planned. You'll learn a lot doing this kind of repair. TAKE YOUR TIME, work with someone who has done this sort of thing before if possible, and do your research. The Internet will provide you with lots of helpful information. Removing transmissions isn't terribly complicated, but there is a fairly strict procedure to follow.

Also.....while you're in there, replace the o-ring behind the plate that holds the front main seal in place. It would really suck to make the repair you're planning, only to have some $3 o-ring fail not long afterwards. Perhaps the selector shaft seal (also very inexpensive) might need changing as well.

You could eliminate a lot of potential future headaches by addressing those other 2 things while the transmission is out of the vehicle.

 

[Mr C]

Sounds like classic torque converter drainback. As mentioned front seal has failed...probably hardened up from age & heat.

 

[Gerald Morris]

Front seal. Mine is shot too, along with all the others on my 727. Drop the tranny and do the rear expansion plugs while you're down there. In this, I've been fortunate thus far, but plan to do them this Fall. Need to do the front passenger side behind the motor mount too. Surprisingly enough, the rubber temp bung I put in last summer has held very well, but I don't trust it to hold much longer. Be SURE to flush your cooling system and use ONLY distilled water and good antifreeze thereafter. I do and it keeps Mathilda running cool even in 115 F summer traffic down here.