Chewing up UJ bearing - time to open the final drive?

1998 Disco 1 with 280-ish km. Many of them offroad: lots of desert and riverbed miles on this drive-train.

So a couple of weeks ago I changed the UJ bearing by the transfer box on the front propshaft, and now - after about 750 mostly highway miles - there’s already a little play in it.

What’s going on here?

Other (related?) symptoms: (a) driveline clunk when changing speed (driving, take foot off accelerator, put foot back on and there’s a clunk as something takes up slack somewhere).
(b) shimmy in the front between 60 and 65 mph.

Propshaft yolk is good – not worn oval. Possible I screwed it up installing the new bearing, but I don’t think so. Same with bearing: It felt good when I put it in and the circlips are still on it. The prop-shaft itself was hard to slide in and out / extend and shorten, but I greased the hell out of it and it seemed to be smooth when I put it back in.

Ball-joints are all good. Wheel and swivel bearings and pins seem ok (pre-load set 5000 miles ago) . Play on the propshafts is maybe 3-4 degrees (back and front) with no handbrake, marginally less on the front propshaft with handbrake on.

There’s a little play in the drive hubs – I’ve got new flanges ordered but it’ll be a couple of weeks before I can put my hands on them.

I can’t feel play in the transfer box output shaft – but I didn’t take the propshaft off to check it: can you feel play in the transfer box flange / bearing with the propshaft still on?

I’m thinking that it’s going to be something in the front final drive – something(s) loose in there that’s clunking, shaking up the propshaft and screwing the UJ, and causing the shimmy.

Any other - easier to fix - suggestions before I start pulling the axle apart?

Did you fit quality part or Chinese?

GKN...

Is the vehicle lifted, and if so by how much?

No lift.

Did you give them a shot of grease after assembly? Or possible set the bearing caps to far? or even loose a needle bearing when you assembled/installed them?

(1) grease: greased and greased again. (2) bearing caps too far: don't think so - circlips just barely slipped in (3) don't think so either - the joint was moving well and nice and tight when I put it in. If a needle were out of place wouldn't the cap have sat proud of the circlip groove?

Rabat Matt said:

What’s going on here?
Other (related?) symptoms: (a) driveline clunk when changing speed (driving, take foot off accelerator, put foot back on and there’s a clunk as something takes up slack somewhere).
(b) shimmy in the front between 60 and 65 mph.

Click to expand...

Driveline clunk, could be rear suspension "A" frame balljoint, very common problem.
Shimmy can be caused by strange type, (choppy), wear on front tyres, try putting rear tyres to front.

Yep - I used have two clunks. When I replaced the A-frame balljoint one of them went away! That was a year ago. Same with the shimmy - there were more before I had the wheels balanced... actually, to be fair, there were more until I had the wheels balanced the second time. The first time I had them balanced there was a noticeable uptick in the highway shudders and shimmies. I dunno - I think they tried to balance the wheels with string and bubble gum and stuff. So I took it somewhere else to have the wheels balanced and it all got a lot better. I also took the wheel that had the noticeable flat spot off the front and hung it on the backdoor as a spare. Then things got better. Only one shimmy!

Which is all to say that I'm not sure that the shimmy isn't from the wheels. Could be. But I don't think there's much more that I can do to eliminate the possibility.