Yotadawgjr

Lubed my zerks over the weekend with Moly. I had the typical rear driveshaft thunk when it was really cold out / while getting on/off the throttle in 2WD.

When I did the zerk for the slip joint, grease came directly out inside the shaft. I have no cap on the end either so was easy to tell that. I tried putting my finder on the inside of the shaft and put pressure while pumping, then grease possibly flowed somewhere else. No grease is visibly oozing out of the sliding interface of the shaft.

I'd like to understand how the grease is supposed to flow in there. Does it just fill the inside of driveshaft (so cap needed for effective greasing) and through pressure run to the splines? Or is there a more sophisticated path to the splines which may be broken on mine?

Pics would be great, maybe dissabled driveshaft, only thing I can find are the assembly drawings. 3rd gen 4runner

MudHippy

Where's the cap?

Because...yeah. You need one to be there if you want to grease the splines with the zerk.

Yotadawgjr

It's gone, not sure if it was ever there, I only recently started lubing the zerks myself, my mecanic would do with oil change usually so I don't really know.

Can you explain the grease path? Does the grease fill the entire hollow end and then push into the splines? Is there supposed to be a hole on the inside of the shaft directly in-line with zerk?

MudHippy

Yoke is hollow. You fill it with grease through the zerk. If the cap is in place, the grease is forced out along the splines. If not, it won't be. And you'll have a continual grease contamination/lack of lubrication issue.

Don't overthink it.

Yotadawgjr

Ok so if zerk wasn't there, you would see right into shaft?

I could see why people recommend lubing the driveshaft with the truck on the ground, I'm beginning to think my mechanic pumped too much grease with it in the air, then when it set down or when suspension was cycling, off went the cap.

I have the assembly drawing of the driveshaft but cap isn't showing. Do you have a part number by chance? Any way of lubing the spines without it, short of removing the driveshaft?

MudHippy

I doubt there's a part #. But you might be able to replace it with something you can find somewhere though. It's an expansion type core plug(a.k.a. freeze plug). Not the cup type like commonly used on/in an engine block. Same basic theory, they're just installed facing the opposite direction. There not something I know a whole lot about actually. Had to look it up to remember what the different kinds of plugs are called. Trick is finding the right size I suppose.

Yotadawgjr

Ok makes sense, thanks for your input.

I'll so some research and find something that works. I imagine it's not hot horrible to run it no cap since it's generally facing downwards . thinking I'll just try to pump a bunch of grease in there for the time being and cycle the suspension.

MudHippy

Wrong again...I think. I'm having one of those days I guess.

So...I think it's actually whats called a disc or dished type. Because I'm remembering seeing one of these caps we speak of that wasn't fully sealed. It wasn't fully seated rather. And I could see what appeared to be the edge of it(after wiping off the grease that was leaking out there). And it didn't appear to have a wide sealing edge like an expansion or cup type. So I'm 99% certain it would be the disc/dished type. Looks similar to the expansion type when installed.

Yotadawgjr

Hmm ok wondering if I can get one of those in without removing the slip yoke. I've been also looking for the cap/plug online with not much success. I guess Toyota would sell it new as part of the slip yoke.

Appreciate all the info!

Yotadawgjr

Does anyone know the inside diameter of the slip yoke?

I read stumbled on Jeep thread where guys would use expanding rubber plugs to solve this issue.

Malcolm99

You will have to remove the slip joint, remove the u joint to press the plug in place nice and true, go to the wreckers and get one complete easy fix, 8 nuts and bolts later 20min job and you have 4 nuts and bolts to spare,.