MTFCA Forum

As you can see in the picture, everywhere I go when I park I leave a blob of grease under the car from where the driveshaft meets the transmission.

I realize that something is wrong here but I don't know what it is. Is there some kind of seal that's gone bad?

From the stain associated with it, it looks like some engine oil is mixing with ujoint grease and you're losing a little oil soaked grease. This is fairly normal. The more worn the 4th main is, the more oil works out. In some rare instances, the tailshaft is missing a welch plug due to being missed at rebuild time, but that results in more oil than it seems you have. In worst cases, excess oil will work its way to the rear end and overfill the rear end, leading to leaks out the rear wheels worse than normal. I once knew someone who thought they had struck it rich in the oil business as they were constantly having to drain their rear axle (not thinking about all the oil they were adding to the engine). There is no seal missing, though if you have a little extra play at the drive tube ball and rear main, you can purchase a shim that will take up some of the slackness and form a little more of a labyrinth for the grease to work through.

Okay, thanks!

I keep a sharp eye on the oil and it's not down at all. Also, I checked the grease cups and there's plenty in there.

That having been said, a few weeks ago I REALLY greased that joint. It took a lot before it was full. I wonder if I put too much in there.

I was actually going to ask if you had really given it a good going over recently. In any event, these things do throw it out, and if too full will self correct, and then continue to leak..HAHA. In any event, a couple turns or a cup of grease now and then and you're fine. Just don't simply fail to grease it and drive it for 20 years. The ujoint is a very robust part. And the only grease that's doing you any good is the grease that made it's way into the bearings...all the extra is just that...extra.

Excessive grease departure in that area could also be indicative of a worn ball on the end of the torque tube. Simple test is to pull the hand brake lever back & forth rather aggressively and watch for any movement of the ball moving within the collar - you'll see it if it's worn - vendors sell a steel/tin shim for a remedy.

The time to worry is when it stops leaving it's mark. At that point you're out of oil and grease.

was thinking of adapting something like this

Scott: I zoomed in on your picture, make sure that both the upper and lower plugs are in place at the U joint pin access points. It is hard to tell because of all the grease but it looks like the upper plug may not be installed and a missing lower plug could allow grease and oil to drip as you show in your picture.

Looks as if the 4 bolts need tightened up and definitely you need safety wire and cotter pins on those four bolts

https://www.modeltford.com/item/2571MB.aspx

Why is there much more radius rod end thread showing on one side?

Scott, you might check that there is just one gasket in the ball joint assembly. It goes between the back of the hogs head and the ball cap. Some mistakenly fit a gasket on both sides of the ball cap, thus opening up the gap between the ball and the retaining cap holding it in place. This will exaggerate the same problem that a worn ball will give, play at the ball and easy egress for grease.

Allan from down under.