Hello all! This is my first post so bear with me if I make any mistakes. I should probably add that I am probably a youngster by the standards here (early 20's), and thus am doing a LOT of learning to figure this all out on my own. Please bear with me if I don't yet know any terms, phrases, etc. Also - as you are about to see - I am a very detailed person. I type extremely fast so writing a lot isn't a big deal to me and, I will bet the details will make this answer a lot easier to find.
Quick history: I got my mostly original 48 Stylemaster at auction back in May and have been having fun learning as much as possible and getting my hands as dirty as I can to fix it all. The car was beautifully restored to its original condition I believe in the early-mid 2000's and then sat in some sort of climate-controlled display up until I got it in early 2022. However, despite looking great, there have been many interesting mistakes/issues I have found from a mechanical perspective that went unnoticed since the car wasn't operated. Example: The float in the Rochester B was upside down... so obviously the needle valve's ability to operate properly was fubar. My point is that if any part of this post appears to be something that was simply put together wrong, or something (a seal) is just missing, it wouldn't surprise me. This issue however has somewhat stumped me simply because I can't figure out what this part is called in order to then look up information on it, how it's assembled, why it may be leaking, and get replacement parts/seals. I also can't seem to find anything in my shop manual (or the Old Car Manual Project manuals) about it, although not knowing what it's called does make that more difficult.
Specifics: 3-speed on the tree which I believe is original, replacement 1959 manufactured 235.
Should the photo's on this post ever get deleted somehow, there is a bright silver cuff that screws onto what I believe is the output of my transmission, and seals it to the enclosed drive shaft. This is directly above the spring for the parking break. I am seeing transmission fluid leaking out from the cuff and onto the spring below it regardless of whether I drive the car or just let it idle.
What on earth is this silver cuff and/or sealing assembly called?
I noticed rather quickly when it was leaking that many of the threads were visible, so I tightened it down first by hand, then using a strap wrench, although there were still a few visible threads despite me tightening it down as much as I could. If tightening this down was the wrong move, oops, but I again can't find any information on what this thing is called or how it should be assembled.
Much to my surprise... after just a little bit of driving, it unscrewed itself??? After that, I think it was either completely off or only hanging on by a thread or two. I ended up pulling it off to reveal three metallic cuffs/shims inside it. A thin one, a thick one, and another thin one. From the research I had done, I was expecting to see a cork seal in here as well. But, to my surprise, looking back into the silver cuff and into the inside of the joint, I don't seem to see one...
This post seems to be talking about something similar, although I am not confident it's the same exact thing: https://vccachat.org/ubbthreads.php/topics/449049/driveshaft-leak.html It indicates there should definitely be a cork seal in here - if it's talking about the same thing.
And that post indicates this... https://www.chevsofthe40s.com/detai...Ball_Seal_Kit_For_Drive_Line_Manual.html ...kit has the cork seal that should (potentially) be part of this assembly. If truly missing, I would assume that the cork seal goes between the furthest back (in regards to the front/rear of the car) metal shim and the metal cuff that screws on. Also, it seems that the forum post indicates the cork seal has a cut in it such that it can be put on without having to disconnect the drive shaft... I really hope that's true.
Any information on what this part/assembly is called, how it's assembled, why it may be leaking, if there should be a seal, and if so what seal that is called and what's required to put it on, would be greatly appreciated.
As to the pictures you posted. There is the screw on collar, the one thick washer, then either a cork or rubber (depending on which seal kit you buy) seal, then another thick washer. You will see in the above thread.
After looking at the above thread you still have questions, ask them please.
Of course, there was a thread I hadn't found... And, somehow I didn't realize that the center ring of the three was rubber... Genius!
Those videos/links are very useful! I'll add this one as another I ended up watching: Certainly helps to know it's called the torque tube in order to find information on how it's put together!
I am not yet sure if I need to actually replace the rubber seal yet, as surely even when new (and/or when cork) it's going to leak if the collar comes 95% of the way unthreaded. For now, I suppose I need to clean the oil off again and tighten it down and just see what happens. I genuinely have no idea how it managed to undo itself...
The torque ball and threaded collar are I believe of a later vintage, early ‘50s. A better design than the original. I have a ‘46 and replaced the original one with the later model and am pleased with the results.
I still have not managed to fix this stupid thing. I really wouldn't care if it leaked a little but instead, it continues to unscrew itself, and I can't figure out how/why.
I have tried to tighten it by hand, I have tightened it with a pipe wrench. I have tried snugging it down to the point it began to spin the larger tube of the torque tube itself. I have even tried tightening it a bit past that by holding the tube still. Even at that level, there are still 1-2 threads visible on the tube so it's not "all the way" but it's clearly very very tight. Last I pulled it apart the poor rubber seal looked like it had been squeezed rather strongly by my last tightening job, so it's clearly not from lack of trying to snug it up.
I have tried cleaning the lubricant off the threads and even applying small amounts of Permatex aviation #3 (whatever I used on the fuel lines) on the last threads to try and give it just a little more grip. Even then, just driving around at 20-40MPH around the block starts to loosen it again (Backs off a few threads). After any serious driving, (10+ miles) it will only be holding on by a thread or two and thus obviously not retaining the fluid as it should.
I am wondering if the shop that worked on my car (who fubbed multiple other easy items like the timing) overfilled my transmission fluid and if somehow that's building up the pressure to push this cap off? Given this part touches no rotating objects, internal pressure pushing it off is the only thing I can think of.
Something that just occurred to me... Are the two washers and the gasket supposed to get pushed INTO the torque tube....? They don't look like they would fit... But it almost looks like it would be possible and that makes more sense in my head as to how this thing forms a tight seal.
The 2 washers and seal fit inside the knurled nut or cap. They seal on the end or face of the torque tube. That face should be clean, smooth, and square. The surface of the bell extension needs to be smooth and clean.
I have had the best results when I use a strap wrench to tighten that cap. Any type of pliers or pipe wrench distorts the cap. It flattens the cap where the jaws are clamped. That makes the cap feel tighter than it really is.
What I am going to tell you is what I had read somewhere and decided to give it a try.
Mine had the cork seal. Never could get it to completely stop from a small leak. So I followed the recommendation. Backed off the screw cap, slid the seal and washers back. Wiped it down with acetone to remove any oil. Filled the gap between the tube and ball with a small amount of oil resistance (important) RTV. Then cut a 2" id by 2 1/4" od o-ring and fit around the torque tube. It had a little slack in it so I cut out enough to get it the exact size of the tube. Glued it back together with super glue. Gave it a few minutes to dry. Slid it into the rtv. Slid the washer, seal, and the other washer up against the o-ring then tighten the screw collar as tight as I dare. So far it has not leaked.
One thought, why not put a hose clamp around the tube tight against the screw collar to keep it from backing off. Just a thought. That I also do not know how that happens?
This is just what I did and take no responsibility if you try it!
Gene - Something is awry here. My '40 has a felt washer between the two steel washers shown above. It is the original felt washer that came with the car. Back when it was my work car I ran it about 20,000 miles a year. I would service it every other weekend and would occasionally see a drop of oil on the knurled nut. I would snug tighten it "by hand" as I thought that was why the nut was knurled. The '40 has never leaked more than the occasional drop. That 82 year old felt washer is still in place, hand tightened, and not leaking. There almost has to be excessive vibration to cause the nut to back off. especially when it is tightened with a wrench.
I have to agree that this is a case when “new” is not as good as the original. Unless the cork has a lot of rubber in it I expect that the seal will not work well with the back and forth sliding motion.
I do suggest that the paint on that portion of the bell extension might be part of the problem.
I have tried using a strap wrench a few times, that was the first thing I tried after just hand tightening, and thus was before I got a pipe wrench. It still backed off sadly.
Something that occurred to me though while looking at it last time is that the rubber seal doesn't move smoothly along the tube - despite the oil getting tossed up, it doesn't seem to really lubricate the movement of the seal. I am wondering if the drag force is what is unscrewing the cap....? Out of curiosity, I pulled it apart and got some grease not only under the seal but also on the length of the shaft so it can slide much more smoothly. I know it shouldn't really move all that far, but I don't see any harm in trying it.
