Front Driveshaft spline slop

[Hunter79764]

Possibly stupid question... I developed a noise coming from the front end ('87 3/4T Burban, ~stock with 100k miles) that I isolated to only when hubs are locked, and then further to the front driveshaft, specifically the splined slip joint. The driveshaft has probably 1/8"-1/4" 'wiggle' to it when you press from the side at that joint. It doesn't seem to have much rotational slop, and the U joints seem to be fine in every direction, but basically every revolution of the driveshaft it flops around and makes a 'womp womp womp' sound. I temporarily packed some stuff in there to hold it in place and the noise went away, so I feel confident that is the source.

I know it is dry, seems like nothing has been lubed on the underside of the truck in many years, including the driveshaft. Is it possible that pumping some grease in there will center things back up, or is the damage done? If damage is done, is there any way to rebuild that joint, or am I essentially looking at a complete new driveshaft?
Thanks in advance.

 

[Bextreme04]

I'd replace the seal(its just cork) and the nut and then pump it up with grease. The grease helps keep it nice and tight. If it's dry it will just flop around like that. Its a dana/spicer part and is only ~$10 from Amazon

https://www.amazon.com/dp/B00GAPISNU/

 

[Hunter79764]

Huh... Maybe I need to look at some pictures and look at mine closer, but I don't think that part is on mine at all... Might do the trick. You have to pull the shaft apart to put it on there, I take it?

Thanks.

 

[Vbb199]

Huh... Maybe I need to look at some pictures and look at mine closer, but I don't think that part is on mine at all... Might do the trick. You have to pull the shaft apart to put it on there, I take it?

Thanks.

It's the cap that on the axle yoke end of your driveshaft.

Pull it off the other half shaft end, the cap pictured in the Amazon link comes off.

That'd be a good time to inspect your splines and see if they're twisted, rolled, or stripped.