I was going to say, if it's the N/S one that's leaking, to check the gear change oil seal on top of the box first. I thought we had leaky driveshaft seals on both the Panda and Punto which turned out to be this seal and not the driveshaft seal. However I think you've already done that selector seal earlier? Didn't you?
As regards getting the driveshaft out of the gearbox - The end of the shaft inside the gearbox has a groove around it as does the output side of the differential into which it fits (it's a splined shaft). Sitting in this groove there's a spring ring (snap ring) which is a "snap fit" - hence the name. One set of these splines, usually the one in the differential, (but not always) has a chamfered "lead in" which, if you exert enough force on the shaft, causes the snap ring to compress and the shaft can then be withdrawn. The snap ring should come out still on the shaft.
The difficult bit can be getting the ring to compress into it's groove. Some just about fall out by themselves (that would worry me a bit and I'd probably fit a new snap ring on reassembly). However most need some "persuasion" to get them moving. This is my favourite "persuader" with a half inch square drive ratchet alongside for size comparison:
View attachment 218460
The end of the lever goes in between the back of the inner side of the driveshaft joint and the gearbox casing. Often I find levering against a retaining bolt head works well. I would caution against levering too hard though as you might crack the gearbox casing if you get really violent (I've never done this. I think you'd have to get get pretty rough with it, but it's as well to know it is a possibility). I find a "quick jerk" works better than a sustained slowly increasing application of force. If it doesn't pop out - and it will "pop" when the hold of the ring is broken - with moderate force being applied then stop and rotate the shaft a bit (maybe a third to half a turn) and try again. If you start applying extreme force you may find that rather than compressing the ring into it's groove the splines will cut into the snap ring and jam it. If this happens you've got a real battle on your hands. So be firm, It does take a goodly "jerk" to pop it, but if it's not moving rotate the shaft and try again in a different position. I've also seen myself with 2 levers, one on each side, "rocking" the joint from side to side if I've got a tight one.
Once you've got it out have a good look at the ring. If it's at all damaged or if the shaft virtually fell out by itself (most likely because the ring has lost it's "spring") then fit a new ring. The most common damage is that the splines may have "bitten" into it as it was forced out of the final drive (differential) If you see signs of this I'd renew it because, although it might go back in just fine, if you need to later remove it again it may well jam in place.
You can also run into problems reinstalling the shaft. The outer edge of the splines in the gearbox are tapered to help compress the ring. Typically you'll find there is a short length of shaft spline which you can enter into the gearbox which lets you get the splines lined up. Then the ring comes into contact with the end of the diff gear splines and a goodly shove is needed to compress the ring into it's groove. The problem, often much worse when you've fitted a new ring, is that the ring will drop to the bottom of it's groove in the shaft so can't properly enter into the chamfered "lead in" in the diff gear. People don't understand this just thinking "Oh, it's a new ring so it'll be tight, so I'll just hit it hard with a big hammer" then they are surprised when the ring gets "transmogrified" and, perhaps, irreparable damage gets done to the splines! The "trick" is to keep the ring centralized on the shaft with some grease. Here is a clip which shows the snap ring and how to keep it centralized with some grease:
https://www.youtube.com/watch?v=8s8VZShBB5k
The "special" transmission grease is a grease which melts into the gear oil so won't tend to block up small oilways inside the gearbox like, for instance, a normal wheel bearing grease, which won't melt. If you don't want to buy this special grease then Vaseline (Petrolium jelly) will do just fine as it will melt and emulsify into the oil once the gearbox warms up.
Good luck with it Chris. Be prepared for some oil to leak out when the shaft comes out. In my experience they usually come out reasonably easily with a firm "jerk" of the lever and you'll be very unlucky if you get a "difficult" one. When reinstalling they sometimes need to be "rammed" in with some determination but I find the plunge movement in the inner joint lets you use the shaft itself a bit like an impact hammer which helps seat the ring into it's inner groove. When you think you've finished give the inner joint a good tug to make sure the snap ring is holding it in place.
regards
Jock
PS If the old ring is in good condition and the shaft was being held in properly by it I tend to just leave it be and reuse it. If you fit a new ring it has to be worked onto the shaft over the splines which, I think, tends to expand it a bit and often then makes it a bit more difficult to get it started back into the diff gear spline.
