That is transmission oil seeping out of the joint between the torque tube and torque tube ball. It has a gasket sandwiched between two thin washers and the joint is threaded. Take a pair of channel lock pliers and tighten the knurled ring as much as possible. You may be able to slow the leak but, honestly, nearly all leak or seep to some degree. Kent
Doesn't look like a leak to me. Heck it's barely even wet.
Like Kent said, there's a cork gasket between steel washers. Snug up the big nut and you'll be golden.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Two seals. One at the universal joint ball and one at the propeller shaft splines. They naturally wear out by motion.
The rear axle on leaf springs can move up and down (pot hole), left and right (curve) , sideways etc. The propeller shaft follows the rear axle. This motion causes the ball to swivel. The rear axle can also move in and out and so does the propeller shaft on splines.
If the ball wears (causes leaks) and forms a rut/groove or rusts badly, the ball can stop moving freely. If the ball stops moving the seal at the splines wears quickly. Tightening the big ring to tighten the seal at the splines works to seal leaks for a time. But there is a limit to how much the big ring can be tightened. Time to fix problems.
The ball joint can be frustrating to fix correctly so many avoid this work unless the leak is severe. Just keep an eye on transmission lubricant level.
A little leaking at the torque tube and engine rear main seal is normal for these old trucks. It's no shame. Use a drip mat.
Last edited by buoymaker; 03/31/20223:06 AM.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
The ball can be a PITA to adjust. The service manual says it needs to be done with the ball separate from the torque tube and without the cork seal ring, and it's shimmed with multiple gaskets where it bolts to the tranny. You start out with a bunch of gaskets, and if it moves too easily, you remove a gasket and try again. Once it's fairly hard to move by hand, then you take it loose from the tranny and install the cork seal and bolt it to the tranny with the proper number of gaskets. One issue is that if the u-joint has ever let loose, it will tear up the inside of the ball and also create lumps on the outside of the ball. I had two like that and needed to smooth off the ball of the best one of the two so it moved smoothly inside the socket on the tranny.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Some time ago it was suggested using National #327 O-ring instead of the cork seal sandwiched between the washers as mentioned above. I have not used this so I cannot verify the viability of it's use/application.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
33 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
I knew a guy who hung a can under the rear main of his Model A (which was famous for leaving a trail.) He would occasionally take the can out and pour it back into the engine.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.