70Cutrag

So, we finally got some decent weather here in Cleveland, time to blow the dust off my 70 convertible project. My hope was to get it ready for a new top, but looking under the car, the dreaded red puddle from the rear seal. This has been a constant problem with this car, but only when it sits in storage. I replaced the rear seal myself 2 years ago, it leaked, then I had the entire transmission rebuilt (but a very reputable tech) and here we go again. It's the rear seal, I'm sure.
After it was rebuilt last summer, I drove only a few times around the block (no glass, bumpers, lights, etc) and it was great. Fluid level right where it should be and dry. Parked it in the garage and it sat all winter. I have not started it, but the fluid level, cold, is a good 2 inches above the full mark.
So, this may be normal or not? Could it be that the converter has drained back into the pan from sitting untouched for 4 months? Now the level is high? My cure is just to start it every few weeks?
Ok, unlikely, but just a thought.
My only other plan of attack is to pull the driveshaft and get the yoke replaced. It looked pretty good, but did have some slight rust on it.
Maybe it slowly seeps along the rust after months of neglect?
Any advice welcome, this bleeding needs to stop.

RetroRanger

Sorta normal the converter drains back and overfills the pan the weakest link seeps the overfull fluid, usually it's the dipstick seal.

You could start it more frequently or just plan for it and put a tray or absorbent mat under the car when stored

cherokeepeople

yup mine leaks too i don't worry about it.

ELY442

Mine too, due to the cold weather, my pan gasket always leaks if I dont drive it enough especially during the winter. I use metal pans or aluminum and due to the weather the pan expands and contracts. We need to drive it out more often then let it stay in one place.

olds 307 and 403

Glad to hear everyone else has leaky GM transmissions.

70Cutrag

How strange, I guess it's normal. I would think the converter drains fully in a few hours after turning it off, so a daily driver would be a daily dripper. Maybe it's an annual event, now that the weather has warmed and the fluid expands? I checked it from October to February, dry as a bone. I've owned this car since 1980 and never noticed it before. It did however spend most of it's early years in a driveway, or occasionally a friends garage. About 15 years ago I finally got a house with a garage big enough for it and the wife's car. 3 years ago it finally moved up the priority list, and I rebuilt the drive train and cared about fluid levels. Now, older, wiser, and **** about things, it bothers me. Oh well, I guess I need to accept this as normal. Thanks to everyone that replied. Today looks like a good day to replace the fuel line. Yard work can wait.

coldwar

If it is leaking from the tail shaft and you know it, check the fit of the rear bushing in the tail shaft housing for excessive clearance with existing front driveshaft yoke, or just have the bushing replaced. Really, any detected wobble is excessive, the yoke oiled should slide in and out the drag of the new seal considered, just right. If the front yoke is then also grooved or otherwise worn on the bearing surface, also find a better one at the same time. Try to find a quality USA made seal.

john paul

mine also leaks and it's driving me crazy. I don't know where it's coming from, but the trans fluid seems to start from above and around the pan area and work it's way back towards the speedo cable and drips into the frame cross member where the trans mount is. my dip stick level also reads about 2 inches above normal. I'm at a loss and so tempted to pull the trans to find out where it's leaking from. so far, all I've been doing is measuring the amount that has leak out and adding that same amount back in. what are the odds that this could be case porosity? Any body have any ideas?
thanks guys

olds 307 and 403

I am wondering if it is rubber seal quality, installing them dry or worn bushings? Either way, all my old trans leak somewhere, somehow no matter how many seals I replace, including bushing replacement and Vasoline.

RetroRanger

My current th350 doesn't leak any appreciable amount, but my dads old th350 would leak enough to make a mess every winter storage, it was attributed to converter drain back from long term storage. IDK why but it was a regular event that never happened during summer driving season.

olds 307 and 403

Mine aren't any amount either, it is just the point that they seep somewhere. God bless old cars.

Greg Rogers

My Cutlass leaked every winter a pretty good red puddle. I finally was tired of it and replaced rear seal and bushing, trans fill o ring, kick down cable and o ring, shift lever seal and trans pan gasket. 4 years now and NO leaks over the winter. I rebuilt the transmission on my Vista and replaced all of those above parts but had a leak. On that car it was leaking out the splines then thru the weep hole of the yoke. I replaced the yoke with one without the weep hole but with the "missing spline". Now neither of my Olds' leak ATF over the winter. It can be fixed.

olds 307 and 403

Yes it can be fixed, if every bushing and seal is replaced, which basically means a rebuild. I went with trans hydraulic fluid which thicker and has helped as well.

Greg Rogers

Actually all that stuff I mentioned can be done in the car. Dropping pan and driveshaft if you need to do the yoke. Actually you may have to remove valve body for the shifter shaft I can't remember... It's not a bad job if you have some tall jack stands, or a car hoist! I wish!

olds 307 and 403

The front pump seal always leaks, even with a new seal. A new bushing means pump removal. I have mine down to seepage on the TH350C and a slight leak at the the torque converter on the 2004R, the best I can hope for.

Greg Rogers

I guess I never had problems with the front seal by the torque converter. My cars have turbo 350's.

70Cutrag

Just wanted to update - I started it up, added about a cup of fluid which brought it back to full, and went for a short drive. It's been a week now and I check every day - dry as can be. Moral of the story, gotta start em' once in a whlle. I'm planning once a month in the winter so we'll see how that works. Thanks to those that replied, it helped me avoid unnecessary repairs.

budg

Im glad its just not me. I ended up putting a pan under mine . I check it and havent had to add much . Its more annoying than anything, but not sure its worth replacing all the seals over.