I have a '79 J-10 and there's a squeak from the double-cardon joint at the rear of the front drive shaft. Can I lube this or do I have to replace it? Thanks for the info.

Look to see if it has grease fittings on it. Most of the ones I've had have the fittings.

Once the noise starts, grease is only prolonging the need for a new shaft (or at least a rebuild).

SD

New shaft? Or new joint? I replaced the front driveshaft 6 months ago. thanks

With CV shafts, you must realize that only a driveshaft expert can properly determine if the ball stud is worn enough to need replacing, or if the slip is marginal...

I let my driveline guy make those calls, I trust what he says. But I never look for a "this repair will get you by for a while" type responsefrom him. I want a "when I rebuild/build this shaft it will last and work like new" response.

All I'm saying is, once noises start, the damage is done.
Lubing all of the 5 zerk fittings on a common cv shaft will only prolong getting is rebuilt or replaced.

SD

might be replacement time then because I cannot find one single grease fitting on this joint. Might be ungreasable?

You might have to install your own fittings and/or take the driveshaft out to grease it.

I have a 2001 Chevy S-10 2WD extended cab with 4.3 V-6. It has 2 piece drive shaft with a double cardan joint on each end of the rear drive shaft. Each double cardan joint has a flush grease fitting for the centering ball. I had to really look closely to find these fittings. I've found that it is easier to just remove the drive shaft to access these grease fittings. It seems I can never get the grease gun at the correct angle if I try to grease the joints with the drive shaft in place.