Do I need a diff, balljoint or something else?

[Shackleton]

Ok so maybe due to my crappy rear springs too but there's been this heavy clunk on pull off for ages (coming from the rear). I ignorantly put it down to a 37yr old truck having a bit of play but now that things have become more serous I was reading Nige's Axle removal bit (thanks Nige!) in the Tech section. He say:

"HUGE "CLUNK" as pulling away from stationary - Many will say this is the A Frame ball joint - often the case - but not so on this problem, I had recently replaced the Ball joint and it went away for a while - then returned again, just as bad.

When this happens its the actual taper in the casing that has worn away forming an oval, once this haoppens it wears the ball joint V fast, I also had trouble getting the ball joint tight, as the wear meant the taper dropped furter down and I ran out of "threads" to tighten onto, even a big VERY thick washer only gave me 2 days use at the recent MWWCE, then on leaving the site to go home "CLUNK" again "

I hope that's what's going on with my yoke but I have to add some symptoms into the mix. (and by the way what taper in what casing, I'm confused? And how can I tell if that's what I got?)

A long time back I imagined that I was hearing a low vibration from the back end and put it down to an aging diff. It was barely discernible though so I could never be sure it wasn't just a combi of road noise and potentially unbalanced prop shafts or something. I just went as easy I could on dropping the clutch.

A few weeks back the truck felt like I'd left the handbrake on, it just seemed to lack power and struggle to go as fast as it should per given rpm. But the engine sounded perfect and no noises from the gearbox. (We're talking Td5 and Defender R380 talking to early RRC axles btw).

But that went away again and everything was fine.

Turned into a pals estate last week and there was a very discernible vibration coming from the rear. Almost a grinding and we're back with less than normal power. But on the same journey that cleared up to but I limped her home anyway. Haven't driven her since. There is nothing outwardly wrong. No oil leaks or signs of trouble. I'm about to drop out the rear axle cause it's time to do a big job with bushes/springs/dampers etc but I've no idea now if I need a diff, shafts, ball joint? I also was wondering what peoples opinions are on replacing the diff with an ARB. I always said I would but is there a point on what is definitely not a competition vehicle?

George

[FridgeFreezer]

Grinding and vibration doesn't sound like a ball joint or half-shafts (they usually just break). I'd be looking at propshaft UJ's and diffs, and maybe transfer box.

Not sure there'd be much point putting an ARB in, something like a Detroit may be a better idea as it requires no user intervention or extra plumbing.

[Shackleton]

Oh don't say transfer box! I paid a hell of a lot for that gearbox only about 15k miles ago! All sounds are coming from the back though.

Prop UJ's are solid. When diffs go do they leave metal traces in the oil, as in are there easy things I can check before stripping?

Thought I'd read that Detroits made noises and were generally 'noticeable' on road which I don't want. My truck is noisy enough as it is.

[Turbocharger]

Drop the rear prop off and go for a drive in difflock to see if the noise is gone/quieter. Definitely sounds like something rotating if you're getting noise and vibration. If I had to bet, I'd put 10p each way on a diff bearing or wheel bearing.

[Shackleton]

Didn't even get the opportunity to do that, it's acting all normal. This better not turn into one of those phantom problems! Oooga booga