Transmission leak at output shaft on 1940

[Garyr1016]

Getting a puddle of gear oil under car, chased the source and it looks to be the rear of the tranmission. What gaskets and seals can I replace on the tranmission? I'll be replacing the clutch, pressure plate and throw-out bearing at the same time. I'd like to not have to redo the transmission, it makes some noise but not excessive, just want to fix the leak and/or leaks. Appreciate the advise

[Matt Harwood]

I'll bet a doughnut that it's the torque ball seal. This is often the most troublesome place on old Buicks to seal. With the torque tube enclosed driveline, the torque ball seal is responsible for a lot of stress and has to remain flexible. It's not unusual for it to fail, especially on a car that has been sitting for a while.

There are a number of fixes, and most suppliers have replacement seal kits that often cure the problem. It's not a hard job, but there is some disassembly required. Your shop manual will walk you through the procedure and once you get in there, it's fairly obvious how it all fits together.

One thing to check that a lot of guys don't realize, is to make sure your torque ball itself is not scored or pitted. If it is, it will make sealing it more difficult. Some restorers, myself included, like to remove the torque ball, polish it so the surface is uniform, and then repack the whole unit. This should cure the problem. If it is badly pitted, consider finding a better specimen (I've bought three for my '41, looking for a decent one) and using it.

Like I said, it's not a difficult job, but time consuming and requiring a little digging into the back of the transmission. I'm sure others will chime in with additional advice and tips, but this is common to many years of Buicks. If you own an old Buick long enough, you'll become an expert on torque ball seals...

Hope this helps.

[Charles2]

I concurr with Matt's response, your torque ball seal is leaking. There is no seal as such on the rear of the transmission of the 1940; the sealing is done at the torque ball. With age and wear, these seals loosen, the ball itself wears and you will get a "pumping" action as the torque tube moves back and forth relative to the transmission. This pumping will empty your transmission of gear lube in short order so, in my opinion, this is a "must-fix" situation. I had to do the job on my '40; I couldn't keep oil in the transmission for more than a few days. The easiest and best way to do the job is to pull the transmission and recondition the ball joint and seal on the bench. This will also give you the opportunity to inspect the transmission and to replace any doubtful bearings and seals as well as a chance to inspect your clutch assembly. To pull the transmission, you will need to disconnect the torque tube assembly at the flange behind the torque ball, unbolt the rear axle from the springs and disconnect the panhard rod and then pull the rear axle to the rear so the transmission can be removed. There is more wrench work to this than I listed above; if you don't have a manual, contact me via email and I can give you a bolt-by-bolt description of the procedure. I have done this job on a lot of 40's Buicks; if everything goes right, you can have the transmission out and on the bench in less than two hours. Good luck.

[Garyr1016]

Thanks guys, you're the best.

I was hoping I could enjoy the ride for awhile before doing any serious mechanicals, but from what you say I need to get after this right away.

Thanks again

[critterpainter]

You also said your trans is making a little noise. If the torque ball has been leaking your trans has had a lack of oil. You would be well-advised to replace the bearings NOW before one fails and does some impressive damage. Also make sure the bushing in your shift linkage are tight so that the gears are fully engaging when you shift. I hate driving a car that likes to slip out of gear.

Bill

[Garyr1016]

Update

"Gunk" seal sealer

I'm not one for quick and dirty solutions as they are usually too quick and too dirty (causing serious problems later). But on this one item I make an exception.

I put in about 6 oz. of seal sealer manufactured by "Gunk" topped off with the transmission with gear oil and ran it gently for maybe 20 miles. Drained it out and refilled with fresh gear oil and this fix took care of perhaps 80% of the leak. I may do this proceedure again to prolong the temperary fix.

This doesn't fix the problem but allows me to delay until winter when I can take my time and do the repair right. Nobody likes to have their fine ride sitting up on blocks waiting for parts during the all too brief summer driving season