Transmission oil leak

[paul griesse]

Hi---new to this forum.....I`ve got a persistant oil leak from my trans on my `31 coupe. Its not overfilled, tower on and sealed securely. Seems to be leaking and blowing back thru the vented bell hosing cover. Has something like this been addressed previously? Many Thanks, Paul

[Mitch]

Hi Paul and welcome to the VFF.
You posted this in the questions and feedback area, so i moved it for you to the main Model A discussion forum

Mitch

[paul griesse]

Thankyou, Mitch

[tbirdtbird]

there is a vent hole in the tower casting, to the rear IIRC. It sometimes gets clogged. Worth a check

are you certain it is the tranny that is leaking?
they like to leak from the rear where the countershafts penetrate the casting, also

[tsalkow]

Hi tbirdtbird, can you elaborate on the tower vent (size, location) Thank you

[DaWizard]

Here are pics of my leaking vent. The first is a blurry above the floorboard, the second is with the floorboard moved back a couple inches to show the hole just below the board.

[tbirdtbird]

about 1/8" diameter hole as shown above.
crud gets in there

[tsalkow]

Thank you, unfortunately it is not plugged so the search for answers continue. Had the entire backside out including the flywheel looking for the leak. everything behind the flywheel was dry ultimately found the problem with the front seal and pan. Put all back and now hemorrhaging trans oil. Drained and carefully refilled with 16oz (600w) plus residual. Level 3/4" below threads in fill hole. Still gushing out the inspection vents when driving.

[plyfor]

What type of 600 wt. are you using? Lot's of discussion about equivalents to modern lubes. Some vendors lube is 140 wt. modern. We try to locate modern 250 wt. oil (Lubriplate, etc.) for straight cut gears. Some stuff will foam in the tranny and migrate. What's the condition of the shift tower and it's parts ? Not sure that the level below the fill hole is a good idea to minimize leaks. Usually lube leaks from the idler gear small shaft as stated.

[tsalkow]

Thank you for the input. The lube is M-533 600 W Axle and Trans Lube sold by Snyder's

[DaWizard]

Ya know, this has been a burr under my saddle for some time now. When I was a kid growing up with Model As, we always used 90wt non-detergent gear lube and never had a problem with lathering up or foaming.

Now days it seems there is nothing left on the market to compare with it. I did notice the last time I had my shifter top off that there was a LOT of unpopped bubbles all over the place atop the "oil". To my sense this is wrong, that oil needs to be clinging on to the gears and not flinging around inside the case to creep out the holes.

It would seem that WE as a group need to go back to basics and find a decent non-foaming gear lube for the trans AND rearend since I don't believe the bubbly crap the vendors are calling "600wt" is anywhere near the sweet oil we had back in the '60s.

Sorry for the rant, but the basic stuff has changed in the last 50 or so years and not to my liking.

Another thing, when I was younger we never used any spray crap on a head gasket, it was place assembly grease on both sides, torque twice and be done with it. That never blew a head gasket, and you can't tell me that the possible removal of asbestos from between the copper plates has changed the compression of the gasket between 2 steel surfaces. Also, when I install a gasket like the valve cover, throw a little permatex on the side you want to stick it to (cover side as it is easier to clean on the bench than the block in the car) and a bit of grease on the other side, assemble to motor. No leaks, and easily reused over and over again with just a small amount of grease applied each time. That gasket will last a lifetime providing you don't break it.

[Jim Baskin III]

Wizard,what about a oil stabilizer to stop the foaming? I know STP is not the answer.

[DaWizard]

Jim, I'm not sure what to use to stop the foaming. If there is an oil stabilizer out there that won't dilute the viscosity then say give it a try, but the biggest problem I have is the current "600w" oil we are forced to drink is way too thin for our application. I don't want or need it thinner.

[Mule Driver]

Checked all fluid levels in my newly purchased 28 model a. Trans was real low. Filled with 600 oil and after a 30 mile trip has a leak at the rear of trans area. Enough to puddle on shop floor. Is there a seal in the rear of the trans that can be replaced to stop this. I,m new to model a,s.

[WMWS]

There is a cover that seals up the two shaft holes at the rear of the transmission. The vendors sell it.

[Mitch]

Clean it off and ck to see exactly where it is coming from. There are two shaft holes on the backend held in place by a metal block and a bolt. That is a common leak point
Also check to make sure the trans vent hole is open.. physically stick a wire, paper clip, or coat hanger in it to verify its not clogged..

[Easty]

Been running straight STP in mine for years. Went from a profuse leak to maybe a teaspoon a season. Shifts better too, less grinding of the gears.

[1931 Flamingo]

Are you sure the leak is from the transmission and NOT the rear main??
Paul in CT

[Mitch]

This thread has evolved into 2 questions. The second one being Mule Driver which I responded to yesterday. The original thread is from June/2017

[Jim Baskin III]

Jim, I'm not sure what to use to stop the foaming. If there is an oil stabilizer out there that won't dilute the viscosity then say give it a try, but the biggest problem I have is the current "600w" oil we are forced to drink is way too thin for our application. I don't want or need it thinner.

Wizard, I agree with you 100% the 600 is to thin.Maybe STP is the answer, but the foaming bothers me.

[Fixitphil]

I don't know too much about tranny leaks but, getting back to his original question, there is a seal that Mitchell Overdrive Mfg has developed that is supposed to take care of the leak in the front of the tranny from the shifting shaft holes that extend through into the bell housing.
Our Club, Charter Oak Model A Club of Visalia, CA, just put on a Seminar hosted by Steve Mitchell of Mitchell Overdrive. He introduced a seal for those two holes, ("The Real Deal Transmission Seal" they call it) that you can install through the bell housing inspection cover to take care of that leak.
I just installed one of these seals in my wife's Slant Window, but have not been able to test the value of their seal. I had a lot of trouble installing the seal but now have it down pretty pat. It doesn't take a lot of know-how as I'm not a mechanic, but I did it and could do one a lot faster now.
Phil

[Fixitphil]

I forgot the pic of the seal. It cost $35 but my wife won this at the Seminar.

[tbirdtbird]

We pump in an entire tube of grease from the Lincoln air grease gun, then fill the rest of the way with 85-140.
Works well, nice and thick

[Dennis]

I agree with Fixit Phil in this case, especially if your leak is in fact trans lube in the bellhousing. Take off the inspection cover on top of transmission bellhousing. With a flashlight and a mirror find the 2 holes where the shifter shafts go through the bellhousing. If there is an indication of oil dripping down on the inside of the bellhousing, then there is your leak. The cost of the Mitchell real deal seal is worth 10 times over in comparison to the frustration of refilling . It could save your transmission from running too low of oil and resulting in gear and bearing failure. There are steps you need to take to prevent damage to the aluminum piece that is held with longer supplied bolts. I don’t use the hard rubber seal that fits over the sleeves going into the bellhousing. I use ultra black silicone and make sure the surfaces are clean and dry. Remove your shift tower so you can visibly tell it assembled without getting damaged. I usually do the installation with the transmission separated from the engine because either the bolts are too tight to get out or my oversized hands will not fit. Also make sure oil is not leaking from your clutch release bearing housing. Bearings on the input shaft with a seal on the front side of the bearing are advised here as well the main shaft bearing having a seal on the rear side. Reverse idler and counter shafts leaks I’ve had the best luck by installing with o ring sealed shafts that have a groove in the shaft.

[Mitch]

These are available for the back end of the trans if it's in the car

https://www.brattons.com/transmission-shaft-seal-set.html

Whenever we redoe a box the o-ring styled shafts go in

[Beauford]

Clean the area and shoot clear flexi seal on it. Mine doesnt leak any more or you can pull the trans and put the .50 "O" rings on.

[Easty]

For what it's worth, I was given an A transmission in 2012 complete with top. It had been in a Vermont barn since 1947. When the discussion came up about proper viscosity lube for our transmissions I took the top off that unit to check what they were using and found a molasses like thickness and colored lube. It has an odor that a Steam Punk guru would kill for. I would judge the viscosity is close to STP! Go figure. This lube is way thicker than the 600W we get from the jobbers today.

[Mitch]

You can send out a sample to a petroleum lab and have it analyzed.

[Mule Driver]

Thanks for the info Fellers. Will check all these responses out as soon as my back gets better and will let you all know what turns up. Thanks.

[DaWizard]

Heh, good time for a lay down on the floor. Fix yer back and check the leaks