I am working on my 1941 Chevy and currently trying to replace the torque tube seals/cork in the U-Joint Housing. I've read everything that I can on the Filling Station site and also threads here, but I'm still a bit confused and don't want to mess this up. Can someone help me with the following questions:
i) Beside the cork seals for the bell, is there a seal in the torque tube to stop oil from passing from the bell to the rear end down the torque tube? My kit came with 2 corks, one bevelled and one not bevelled. And also 6 "paper" gaskets, which I assume other articles also refer to as shims. So if there is a seal that stops oil from going from the bell to the rear end via the torque tube, do I need to purchase something else to stop that? (Maybe that's a bushing seal that does that, but if so, I cannot check that until the U-Joint is removed)
ii) Where does the bevelled cork gasket go? In the collar that holds the bell? Anything else over than the bevelled cork in there?
iii) I note that most articles say to install 4 shims and then check for a good fit. I assume they mean 4 of the paper gaskets?
iv) I note that these same articles tell you to check for tightness after it's all back together, but since I have pulled back the driveshaft to remove the U-Joint, I cannot check it until it's all back together again, meaning if there was adjustment needed (ie. add a "shim" or remove a "shim), I would have to pull the whole drivetrain back again?
v) With the old nut on the bell, there is the old felt gasket. I noted one article here describes two ring gaskets that are in there. I don't know if mine are in there, but I assume they are. Should I re-use those with the new cork gasket? I don't see those in the kit that I have.
Thanks for any help you can provide in this procedure. This is all new to me.
The seal to prevent gear oil from transfering from the transmission to the rear end is behind (to the rear of) the front and rear torque tube bushings. Easy way is to get an Oakie bushing from the FS which comes with a seal.and removing the original busings.
Yes, the beveled cork goes in the retainer and the cork seals against the ball
The shims are the thin paper gaskets. Read in shop manual for using the shims to adjust tension on the ball. The adjustment is made using the ball only and drive shaft must be disconnected.
The two rings were to squeeze the rubberized felt packing. The replacement cork will be used and will require retightening several times like one a week after installation as it takes a lot of pressure to compress the cork.
Regarding the shims, yes, I think I now understand how they go in there. The FS recommendations are to put in 4, I believe, and then check for tightness. But since I've pulled back the driveshaft, I wouldn't be able to check that until it's all back together again, right? I'm just concerned that if I need to add or remove a shim to get the tension on the ball just right, I have to pull the driveshaft back again and that's quite a lot of work. Any thoughts on this?
It seems, based on your answer, that I do not need the two rings then. Just get the cork in there and tighten the heck out of it. I have a strap wrench that I could use - I suspect that would give lots of turning pressure without causing damage.
Tne shims adjust the pressure on the ball. When too tight it wil be difficult to move the ball up and down Correct is when it takes a little pressue to move. This adjustment is made will the drive shaft NOT CONNECTED BECAUSE WHEN IT IS CONNECTED YOU YOU CANNOT MOVE THE BALL UP AND DOWN......
Thank you very much, that does make sense. I think what I meant to ask was: I understand about checking the adjustment on the ball itself. But how do I put the driveshaft in when the U-Joint is inside the bell? What I mean is, with the U-joint inside the bell, how do I align everything as I slide the driveshaft back into place?
Also, for the checking of the adjustment on the ball itself, if I'm only able to pull the driveshaft back about 4", that might not be enough to check the adjustment. This is because I cannot get the driveshaft all the way out due to shocks and flex lines not being disconnected. Would I have to disconnect all of that or is there an easier way to get the clearance that I need? I am worried about breaking the shock connections (which I cannot replace) and the flex lines (which I also do not have).
I really appreciate your help with this. Torque tubes are largely unknown to me.
I have a '41 manual and it does not say squat about how to do what you are trying to do. I have done what you are trying to do a couple of times. Once you drop the driveshaft everything is easier you will have the clearance you need. I must warn you that I tried the "farmer's method" (grew up on a farm) first by cutting the gaskets at the top and installing the new gaskets and same number of new shims just by sliding the ball back and not disconnecting the U joint. Didn't work. Still leaked. So eventually I followed the steps listed below-
1. Disconnect the emergency brake linkage from the cross member just below the driveshaft bell and let it drop to the floor. 2. Disconnect the driveshaft bell and slide it back so that you can disconnect the U joint. 3. Put a jack under the driveshaft aft of where you will slide the bell back to disconnect the U joint and snug it up. 4. Disconnect the cross shaft of the U joint. 5. Lower the driveshaft with the jack enough that the bell is clear of the cross member. You may have to fiddle with the driveshaft to clear the cross member. 6. Remove aft half of the U joint and the bell from the driveshaft and using your new gasket pack attach the bell to the transmission and make the needed adjustments. The snug movement of the ball test is made with the ball removed from the driveshaft. The last time I did mine the new ball cork gasket was large enough that I could barely move the bell with all of the shims installed.
Once you have made the adjustments reverse steps 6-1.
P.S. Be extra careful when removing the universal joint and make sure you have a large jack stand under the end you are disconnecting. The universal joint when removed will cause the drive shaft to fall down towards the floor. If it were to land on your head, etc. the weight could cause serious injury.
Yes, thank you for that. The car is up on a hoist and so the hoist did a good job of keeping the drive shaft in place so that it wouldn't fall out. I imagine that could do some serious damage if it ever did.
Yes, I did see that thread you linked previously. My only concern is that my old gasket in the retainer did not have those two washers when I took it out, so I guess this new one won't work without them? Will this leak without the two washers? I was under the impression from an above answer that the rings were not necessary with the cork replacement, but reading it again I can see it could have been interpreted either way.
I have the correct washers if you decide they are needed. You could try the repair without the washers, but I think tightening the retainer will just cut into the cork gasket causing a sealing problem. Perhaps others may have used a gasket sealer along with the cork gasket with good results when they didn't have the washers?
Uh-oh, while I was away today my father completed the work without any rings and without any gasket sealer and then put in all my lovely and expensive Royal Purple 85w-140 too.
I guess my best bet now is to check it for leaks over the next few days and retighten a bit after a week of driving?
If it does leak, it will leak onto the ground in this case, I presume? If that's accurate at least I would know if it has failed.
The manual calls for only 1 1/2 pints of fluid so I hope he did not overfill the transmission. Best practice is also to put about a cup of the 1 1/2 pints in the speedometer hole at the top of the trans. to lubricate the universal joint. The front of the driveshaft has a bearing in it with a seal behind it. If the bearing and seal are the original ones then trans. fluid could be leaking past them and filling up the rear axle. The rear axle is to have only 3 1/2 pints of fluid in it. Checking the rear axle fluid level should be considered for every oil change.
If the transmission is overfilled it is possible for the extra fluid to bypass the front transmission bearing and end up leaking on the clutch/pressure plate/flywheel causing chatter as the clutch is engaged.
Fortunately he had checked the bearing and seal before filling and confirmed the bearing to be in great shape and no sign of any trouble with the seal. Based on condition, it looks like someone has already replaced the bearing and seal for a new one. Probably some good news that the rear end was a bit low on oil despite a mechanic last Spring (when I first got the car) filling the U-Joint housing with oil at that time which I think helps show it is not actively flowing into the rear end?
He mentioned something about filling the transmission, but not sure how much he added. I believe he said he was not wanting to add so much that it overflows the fill hole on the side.
In regards to the U-Joint, he did add through the speedo hole, but was following the Filling Station guidelines to add only 1/2 a pint. Is that not going to be enough?
He also mentioned that he had seen some pitting on the ball, and so smoothed it up before reinstalling - and confirms that he had tested to ensure a proper amount of slack without being loose there. Car did not leak any oil on my driveway after taking it out for a 1-hour drive today, so hopefully a good sign.
I think I am confused about which items did not get installed. We have talked about a lot of different pieces in this thread.
There are the paper gaskets or shims that fit between the front of the housing the bolts to the back of the transmission.
There is the cork ring that fits at the rear of that housing and runs over the bell of the extension.
There are packing "rings" that install inside the nut and collar that connect the torque tube to the cylindrical extension of the bell.
Which one of these did not get installed?
I would definitely check the transmission fluid level now that you have driven the car for an hour. The instruction to add fluid through the speedometer cable hole is to make sure there is some lubrication in the u-joint area when you start driving the car. The parts turning within the transmission and the sloshing around as you drive the car will make the fluid move back and forth between the u-joint area and the rest of the transmission gears and bearings. The fluid level needs to be at the bottom of the fill plug so the whole transmission and u-joint get adequate lubrication.
If the transmission is under-filled it might not leak at this time.
And overfilling does create problems at the front of the transmission (unless you have converted to a sealed bearing).
It is the metal rings on either side of the cork which goes inside the retaining nut that were not installed. Everything else is.
Yes, there is a half-pint of 85w-140 in the U-Joint through the speedo hole and the transmission was filled up with the same oil up to the bottom of the fill plug.
You might get by with minimal leakage if any at that location. The steel rings are there to help more evenly distribute the clamp load on the cork seal. The idea is that as you squeeze the cork ring to make it thinner it grows in outside diameter and shrinks in inside diameter. That creates the seal. You still get that effect without the rings but you will possibly distort the cork if you make things too tight. The inside of the packing nut is not as square as the steel ring and the end of the torque tube has a slight taper due to the threads. That is a sliding joint so the rings help keep the cork in place and square as the tubes slide against each other.
I would watch things to determine if starts leaking. If if does leak I would consider splitting the steel rings in half and installing them. The packing nut will adequately retain the halves. I think it would distort the ring too much if you only made one split in the ring and tried to wrap it around the tube. If you split the rings I would use a thin cutting disc in a Dremel. You want to remove the minimum amount of material so the rings fit as snugly as possible and cannot move around.
I would also check the fluid level now to make sure things are not overfull. And that will give you a good reference point for future checks.
I want to have a general discussion of the recommended fluid level in a passenger car transmission. Here is a diagram of the 41 Passenger Transmission. Page 5 of the 41 Shop Manual lists 1 1/2 pints as the correct fluid level for this transmission. The second attached picture shows 1 1/2 pints of oil in the transmission which is about 1/4" from the bottom of the right side oil plug. Behind the plug is the top of the Counter Gear Assembly shown in the picture of the transmission. Looking at this picture you can see that this is not very much fluid in the casing, yet lubrication is provided as high as the rear and front bearings and even to the universal joint.
The manual does recommend that lubrication to the universal joint be added whenever the joint is serviced. It is suggested that the fluid be added through the speedometer gear opening. The manual does not specify how much but around a cup has been suggested by some of our posters. Some have also suggested that greasing the universal joint with a good covering of grease should suffice until fluid in the case splashes past the rear bearing filing the area at the bottom of the transmission where the universal joint is housed. So a whole lot of splashing around of fluid serves to lubricate all. In the front of the drive shaft a seal stabilizes the flow of fluid so it does not all end in the axle. The fluid level in the axle should be no more than 3 1/2 pints. Measuring the level can be done by removing the bottom bolt of the axle housing cover. With a good axle seal fluid accumulated in the universal joint area can flow back under the rear bearing into the main case of the transmission.
It is my assumption that overfilling the transmission forces the excess past the front bearing onto the clutch gear which contaminates the clutch/pressure plate/flywheel area causing clutch chatter. Besides the chatter you will find transmission fluid leaking to the bottom of the flywheel. While some might assume this leaked oil is from a bad rear engine seal they need only to rub some of the oil between their thumb and forefinger to notice it is of a much thicker consistency.
In summary I think it is important to adhere to the the amount of fluid recommended by our manuals.
This what our mechanics did years ago and I have always done. Slightly over fill the transmission and in 10 miles the the overfill will find its way into the U joint ball.
You all have been overthinking this thing. Charlie's MethodL
a. Make sure the U-Joint cups are thoroughly greased whether needle bearing or bushing are used.
b. Adjust the bell so that there is sufficient resistance with your arm pressure.before hooking up the U-Joint to the drive shaft.
c. Snug up the packing at the torque tube.
d. Fill the transmission to just below the fill plug. Bent pinky touch is enough. Job done.
Forget about the speedometer thing. You don't need to mess with that because the bell will sufficiently fill from the transmission after a few miles.
I expect this manual advice from the engineers was just a precaution that they threw in the manual in case of dry needles or bushings were installed. Nothing more.
If you want to follow my method and are worried; then jack up a rear wheel and run the engine and exercise the drive-train for about a minute under a no-load condition. That's all you need for the oil to start entering the U-Joint bell and a-slinging ever which-a-way. Is too.
