xantia 1.9TD differential gear change

[xantom]

Hi. I've got a Mk1 Xantia TD that is showing seriously loud groaning symptoms of the final output differential gear going wrong. I've worked my way round driveshaft and wheel bearing problems that might also offer up the groaning rumble but seem to be pointed ultimately at the diff. Generally it groans pretty loudly in a straight line with the loudest noise at about the 50mph frequency. The noise does cut out when I turn left which could indicate a worn left wheel bearing but I've got a new brearing on the left wheel so that puzzles me. I have a 3rd xantia on my drive I use as spares (I've been meaning to but haven't really taken much from it yet) and I think I could swap the diffs. Has anyone done this and can it be taken off the gearbox without removing the gearbox from the car? I'd like to avoid lifting the gearboxes out to make the swap but of course if it's unavaoidable I will. I'd be graeful for any advice on this one. Thanks.

[oscar]

I think it's generally a whole box change as most are one unit and a bench job to remove or extract diff parts.

[Peter.N.]

Its quite likely the other front bearing, although they usually go quiet when you remove the weight that is not always the case, its unlikely the noise would change when cornering if it was the diff, in fact I have never heard of one failing.

Peter

[flying clutchman]

It's definitely gearbox out to shange the diff, easier to change the whole box, assuming it's the same vehicle

[Stewart(oily)]

I took one apart in situ, not too difficult, easy enough to get the crownwheel out, the one I tried would not accept my replacement crownwheel due to it having a different number of teeth, but it would let you replace a duff diff bearing
The crownwheel to diff bolts are held in with the loctite from hell and will almost certainly bring the threads out with them unless you are careful. the car i was repairing ended up having a right side driveshaft to cure its odd behaviour.

[xantom]

Thanks guys. I swaped over the diff from my spares Mk1 with not too much trouble, just released the right hand engine mounting and lowered the engine a bit to get just enough room to maneouvre it out. Fiddly job undoing everything though. Was all a waste of time though because it made no difference to the rumble. So far, diff swapped, both drive shafts replaced ( they were actually pretty worn ) and the left bearing replaced. Now, I suspected the left bearing eventually because I changed it myself in Apr 12 and I think I made a pig's ear of it by whacking in and out rather than pressing so I felt that maybe it was a mechanical karma that it was a bit rough so soon. However, having it replaced properly by a friendly garage made no difference either. All that's left to do is the right bearing, changed by me in Apr 12, but I'm confused if this is the problem because the grumbling switches off when I'm turning left. I suppose I'll end up getting a new bearing pressed in just because I've done this much already but if any of you know of anything else that might be causing such a loud road speed relaeted noise I'd be very interested to learn. Thanks.