front axle knocking,leaking, general grief..

Hello- Just need a little advice before i order some bits for another dirty, ****ty weekend ahead if you will.. My front diffs knackered, loads of slop, ****ing oil and whining away whilst it's at it. Theres also a pronounced knocking sound from the front everytime i hit a bump. Sounds like a ball joint but have ruled out suspension joints already so am suspecting a duff cv joint/bearing. The wheels are are also having the usual wobble at 55-60 mph (had the wheels balanced so it's gotta be the pre-loads?) Basically, thats a lot of shagged parts to sort out so my plan is to just swap the entire hub assemblies and diff whilst am at it from an axle i have and know to be good- well, better at least. my question is do i need any gaskets/ seals to do the job? i dont remember seeing any on the hubs when removed them and cant find a 'diff-gasket' (on fleabay anyway). Will instant gasket or similar do the job? Thanks in advance- just dont want to take my daily driver to bits and be stuck without a car waiting for bits!

rtv silicone sealant will be good

would it not be quicker and easier to swap axles?

I got the pleasure of re-building an axle over the next few months as mine was shagged too, so I don't know how long it'd take you to do the aboce but i chucked a second hand jobby on mine so i wasn't too pressed for time and could rebuild at my own pace

Thanks for the quick replies, chaps-much appreciated!- rtv sealant it is then- take it theres no need for a gasket then? Thought about swapping the axles, but from what i recall removing the hubs and diff was a relatively quick job- taking the axle off would involve removing suspension components/ more messing/less beer-time...

I've just had to replace my front axle as the diff pan and radius arm bracket were shot I replaced the axle casing,all oil seals, bearings, gaskets and gave the axle a good coating of hammerite I think if your going to be that far in to anything you might as well do it properly ONCE

Regards

Nick