Xantia TD: oil weep from diff. housing

Xantidote · Post by **Xantidote** » 26 Apr 2010, 12:13

It may only be a weep, and the volume in the drip tray is quite small (less than 1 cc?) but it leaves a 2-3" patch on the drive overnight. The weep has started since the clutch clip failed last week as I arrived at a giveway line. Unable to recall the sequence of events, but there was a violent thump & I think the engine stalled, presumably as I jammed on the brakes. Maybe this has done something to upset the transmission? The 10 mile drive home involved 3-4 starts of engine with 1st gear engaged, followed by use of 2nd gear. Gearbox is BE3.

The weep is from the lower part of the diff extension, where it's bolted to the main diff housing (3 bolts), and it seems to be moist going up this joint for about 1-2" from each side of the bottom bolt. The offside drive shaft seal is dry as a bone, & no other oil in the vicinity. What puzzles me is that there is an O ring seal between the main diff housing and the diff extension, so how can the oil be getting past it? Perfectly OK & dry until last week. Does this O ring go hard with age? I find it hard to believe that the shock through the transmission would be enough to upset it, or is there more serious damage that hasn't yet come to light. Car has performed fine in the subsequent 200 miles.

Anyone shed any light on this please? I realise I may need to drain the diff, & remove offside drive shaft to investigate further, but unwilling to go down that road until I know what I'm up against.

Post by **CitroJim** » 26 Apr 2010, 12:41

Hi Martin,

I could see a few shocks resulting from a broken clutch clip causing a bit of distress in the gearbox. Tghe RH side is at most risk as it has the long driveshaftr and this can "whip" under strain, especially if there is any paly in the intermediate bearing.

It's ever so easy to remove the extension and reveal the O ring once the driveshaft is out of the way. This page shows the extension and O ring in the first picture.

I've noted thse O rings always look a bit pinched and so it's worth replacing it. Whilst you have the housing off, clean it up really well and examine carefully for hair-line cracks. Check too the main diff housing for any cracks that may expain it.

Replace the driveshaft oil seal whilst you are there. It would be a shame to fix one leak and in doing so, create a new one...

Xantidote · Post by **Xantidote** » 26 Apr 2010, 14:28

Jim,

Thanks for your detailed & quick reply. And thanks for the link for stripping the box down (latter takes me back to doing the gearbox bearings a few years back).

As you say, once the diff extension is off, I can do a thorough check. At 156k, I guess the intermediate bearing will have some wear/play, so good chance there'd be some whip, which hadn't occurred to me.

Can't believe it's just the O ring, so resigned to maybe having to renew the diff housing (out of preference to replacing the diff!)

Xantidote · Post by **Xantidote** » 20 Jan 2011, 12:06

Apologies for my tardy update:

Took Jim's advice, and replaced the circular O-ring between the diff housing and the diff extension (which the off-side driveshaft fits in to). As soon as I'd removed the old O-ring, I could see it had hardened significantly. No cracks/stress fractures found. Fitted the new O-ring seal - no more oil drips

FWIW, I measured the old oil seal in it's flattened state as 90 thou, compared with the nice new one which measured 117 thou.

I accept that it was shock/trauma caused by failure of the clutch cable clip which upset the oil seal, but nevertheless I still find it difficult getting my head round the fact that said trauma upset the oil seal.