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Clutch failure in Colombia: The latest Nacho challenge
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drivenachodrive
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PostPosted: Mon Jun 18, 2012 8:37 am    Post subject: Clutch failure in Colombia: The latest Nacho challenge Reply with quote

I need some urgent help, and thought one of you might be able to offer
some guidance. While driving through the mountains in Colombia, I
believe our clutch went out. The details are a little strang though.
Here`s how it went; tell me what this sounds like to you.

Over the last few days our clutch has been smelling a little bit. We
planned to drive to Villa de Leyva to swap it out. On the morning of
the drive, we stopped and I got out. I noticed oil pouring out of the
junction between the engine and transmission. I turned the engine
back on and the flow decreased to a fast drip. By revving the engine
to 2-3k I could get the leak to stop. I figured it was engine oil, as
it was black. As for why the leak stops under engine speed, I have no
idea. Note that it goes away whether in gear or in neutral.

We drove on, stopping frequently to check the engine oil level, but it
never seemed to drop. After 30 miles the transmission started to get
noisier. Finally realized it must be transmission fluid instead of
engine oil. The van doesn´t have a transmission dipstick, so we
couldn``t check the level. I jacked up the van, opened the fill plug,
and added some fluid. It was about a quart low.

We started on again, but the leak was still there whenever we`d stop.
We decided if we kept driving we could get to Leyva and fix it there.
Transmission sounded fine.

After about 45 miles, while going up a mild hill, it felt like our
clutch went out. We were driving in 2nd gear, and we instantly lost all
power, the engine revved, but the clutch wasn`t engaged. I stopped,
and verified that I could put it in any gear (including reverse), but
letting out the clutch didn`t cause it to engage at all. We waited for a
truck to tow us to the nearest town.

We got a truck to tow us about 4 miles while Nacho idled. When we
arrived, I noticed that our clutch seemed to engage again. I didn`t
want to drive far for fear of getting stuck, but I was able to put it
in reverse and 1st gear and get the van to move as normal for a few
feet.

Is this normal behavior of a failed clutch? It doesn`t make sense to
me that it would fail to engage, but then engage again after cooling
down. Also, as for the leak, I imagine the two are unrelated, right?
My guess is that the main transmission oil seal has failed. Any
thoughts?

We got a cabin here in Susacon, and have a mechanic
who is willing to let me use hiw jack and his muscle when required.
I`ve learned my lesson about letting anyone else touch the van down
here, so I`m doing it myself. I have a new clutch and pressure plate
in the back of the van, and plan to drop the transmission today to
replace them. If the oil seal is bad, we`ll have to seek one out.

Do you have any advice for me as I get underway on this repair? Time
is short, so any help would be greatly appreciated.
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dobryan
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PostPosted: Mon Jun 18, 2012 8:45 am    Post subject: Reply with quote

Others with more experience will respond..... but it sounds like the clutch disk may have gotten fouled with tranny oil and is slipping massively as a result?
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Destructo
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PostPosted: Mon Jun 18, 2012 9:36 am    Post subject: Reply with quote

Brad/Sheena, unfortunately you are going to have to drop the transmission to check this one out. I think the seal around the transmission drive shaft has failed. Also there is something behind the transmission drive shaft seal called an "Oil Slinger". This is a pressed in piece that aids in throwing oil back into the transmission case away from the drive shaft seal. It becomes loose after time and assists with making leaks worse. Here is a great thread detailing who to fix it.
http://www.thesamba.com/vw/forum/viewtopic.php?t=342440&highlight=oil+slinger

The amount of oil you talk of indicates that your clutch disk is buttered up and unable to grab the flywheel any longer. You'll have to drop the transmission, clean the flywheel, pressure plate and install a clean clutch disk. Good luck and don't worry, this is a doable fix on the road. The most annoying part is going to be tilting the engine to dislodge the transmission. Let us know your progress.

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PostPosted: Mon Jun 18, 2012 10:36 am    Post subject: Reply with quote

sorry to hear your troubles,

this is a long shot but if you need help maybe you can contact these two guys on the last page of this thread I'm adding here, they seem to know a thing or two about Colombia, maybe they can help you find a good place for repairs or parts? I know your Spanish is good by now but if you need help translating just let me know.

http://www.thesamba.com/vw/forum/viewtopic.php?t=2...p;start=40
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PostPosted: Mon Jun 18, 2012 11:48 am    Post subject: Reply with quote

Turns out the problem was worse than expected.

I took the transmission out and immediately verified that the oil was indeed from the transmission. Next, I grabbed the main shaft to see how much play it had. At this, the whole shaft came out in my hand. The oil seal was fried, the shaft bearing was in pieces, and the pieces that were meant to be attached to the shaft were absent - a sleeve and a circlip and a stud.

Unfortunately this means that we will need to get our transmission rebuilt. I plan to call around Bogota to see if there are any competent German car transmission specialists. There is a VW parts house there, so I will ask them.

Thanks for the tips and advice. I wish we werent having such a hard time with the mechanical issues on this trip. Seems like we cant travel over a few hundred miles without a major failure. I hope it gets fun again soon...
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Destructo
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PostPosted: Mon Jun 18, 2012 11:55 am    Post subject: Reply with quote

drivenachodrive wrote:
Next, I grabbed the main shaft to see how much play it had. At this, the whole shaft came out in my hand. ...


Oh damn Sad Not fun.
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PostPosted: Mon Jun 18, 2012 12:20 pm    Post subject: Transmission Reply with quote

Save yourself the trouble of looking for a local specialist ,who's warranty if any is in Bogata . Call your well known trans vendor and have one sent to you . That way when you are back home you are closer to your rebuilder should it have any issues .
Many vendors have 2WD units ready to go . They most likely won't give you much for your core ,so it is most likely not worth shipping back .
Go Westy had a Syncro box on the shelf ready to go for me and they most likely have a 2WD unit as well . Many others as well ,such as Darryl from AA trans or the Lengyls or Rancho or AZ trans may be able to get one out the same day.
There is not going to be a cheap way out of this , So get busy and get your CV's greased and get a new clutch disc and pressure plate ,throw out bearing ,starter bushing and Flywheel seal while your at it . Don't forget a slave and clutch master while your at it .Spend the money and cry once .
The trip is all about the adventure .

Stacy
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PostPosted: Mon Jun 18, 2012 2:54 pm    Post subject: Reply with quote

Not so fast. You have a good chance of repairing this on site.

Undo all the 13mm-hex bolts (should be ten in total) that hold the bellhousing to the final drive casing. Pull off the bellhousing, being careful to preserve the paper gasket if possible (it can be replaced with just RTV if it is unsalvageable).

Inside the final drive casing is the final drive, which is the differential and ring and pinion gears. Your problem will be there in plain sight. The trans pilot shaft, the thin one that came out in your hand? that joins the actual primary gearshaft inside the final drive casing. It crosses thru the space about the final drive components and simply threads into the primary gearshaft by an M8 x 1.25 stud that should be projecting from the forward end of the pilot shaft.

Once they are threaded together, a splined sleeve slides over both, and is kept from sliding off, and allowing what happened to you to happen, by a small circlip.

The sleeve is most certainly laying in the bottom of the final drive casing. The circlip should also be floating around in there. It may be reusable, unless it got munched by the R&P. If not it should be a pretty easy part to procure.

If the circlip comes off, the splined sleeve can slip backwards, once it disengages from the splines on the primary gear shaft the pilot shaft can either unscrew from the primary gear shaft and come loose, or more likely be screwed further into the gear shaft (since the engine spinsd clockwise) until the stud breaks off. I am surmising this is what has happened.

To repair it, it will depend on the condition of the stud on the forward end of the pilot shaft. If it is still present, it will be a simple matter of sliding the sleeve onto the pilot shaft, rethreading the pilot shaft into the primary gear shaft until snug, backing off one spline so the sleeve can slide onto the primary gear shaft, securing both together, and then replacing the circlip in the groove on the pilot shaft that keeps it from sliding back.

If, as seems most likely, the stud is broken off, you will have to repair the pilot shaft with a new stud. It's been too long since I had one in my hands, I can't recall if the pilot shaft and stud are of a piece, or if the stud simply threads into the front end of the shaft. if the latter, you can just cut the head off a suitable M8 x 1.25 bolt and make yourself a new stud. If the former, the same can be done and the stud welded onto the shaft. In a real pinch I think you could dispense with the stud entirely and simply assemble the pilot shaft to the
gear shaft with the sleeve and circlip alone, being careful not to pull the pilot shaft back out once you put the bellhousing back on, the pilot bearing in the crankshaft nose should keep it all together once you mate the trans back to the engine. You can see that the stud is only there to guide the shafts together and keep the pilot shaft from backing away from the gear shaft, but it isn't loaded in any way but that, the sleeve takes all the torque loading.

Your leakage while stopped, that slowed when the engine ran, suggests the oil slinger in the belhousing has gone bad. With the bellhousing off, the slinger tube and seal can be driven out of the housing from the final drive side, and new ones installed from the clutch side. These things are shown in the first pages of section 35 of your Bentley. Wait, did you leave home without your Bentley? You two do like to live dangerously.

With the trans out, you also have the option of replacing the engine mainseal, aka flywheel seal, but if I were I would be inclined to leave that can of worms unopened if it isn't actively leaking. How do you tell? There is a hole about 1.5" diameter in the left side of the engine crankcase bellhousing flange (within the engine compartment). Inspect the backside of the flywheel thru the access hole in the bellhousing flange, put your clean dry finger in the hole and see if the backside of the flywheel has a film of wet engine oil on it. If it does, better do the flywheel seal. If it's clean and dry, leave well enough alone.

Whether you aim to do the flywheel seal or not, you should remove the clutch pressure plate and inspect the disc thickness. New ones are just over 9mm thick, wear limit is when the friction surfaces are worn down near even with the rivet heads. Shake the disc in your hands, the springs in the hub should rattle just slightly but if they are very loose, as in most of them can be slid back and forth more then about 1.5 mm, they are heat-fatigued and the disc should be replaced if at all possible. The springs dampen torque on clutch engagement, when they are worn out it will judder on take-off. Also use a straightedge to check the disc isn't warped.

With the clutch plate and disc out you can inspect the friction surfaces on the plate and inside the flywheel, especially for residue of burnt oil. If you see oil staining radiating out from the 5 flywheel bolt heads, the flywheel o-ring is leaking, and that oil will eventually corrupt the clutch so you may want to remove the FW and install a fresh o-ring. Gear oil probably made its way into the clutch from the leaking pilot shaft seal, but if the surfaces aren't burnt blue, you should be able to freshen them up by hand with some coarse sandpaper, and flush with Brakleen, alcohol, paint or lacquer thinner (any volatile mineral spirits) or even WD40 before reassembling the clutch. Treat the milled surfaces of both FW and pressure plate, and both sides of the disc friction surfaces.

Next time you see a leak from the engine/trans joint, get a drop on your finger and smell it. This should become your default response, you will use it plenty owning any rear-engine VW. Hypoid lube (gear oil) smells of smoke and sulphur, engine oil does not. Learn to tell the difference because it will instantly tell you which system you need to anticipate dealing with.

Guess that's about enough for now. We're enjoying your dispatches from the road. Good luck!!
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PostPosted: Mon Jun 18, 2012 8:55 pm    Post subject: Reply with quote

Tencent,

Awesome - just awesome call. I was visualizing this in my mind from having all those parts lined up on my workbench. That's a workable solution and strong possibility on the diag as well.

So, do you have a Bentley manual?

DougM
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PostPosted: Mon Jun 18, 2012 9:27 pm    Post subject: Reply with quote

Make sure the pilot bearing is changed also ,it might have failed causing you this big adventure. Look at the pilot bearing surface on the clutch mainshaft too. My guess is the oil slinger is also loose in the bellhousing.
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PostPosted: Mon Jun 18, 2012 9:35 pm    Post subject: Reply with quote

I had the exact issue as 10cent decribed, it turns out my c-clip had broke and unscrewed it from the m8 bolt...I recall the same feeling when that came out in my hand "Oh....Oh....this can't be good at all can it" to my suprise it ended up being about a 40 buck fix (most of that being new seals I wanted to replace)
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PostPosted: Tue Jun 19, 2012 1:52 pm    Post subject: Reply with quote

Tencent: thanks for the great writeup. I follow you, and think you're probably right. And yes, we did bring our Bentley, as well as a Haynes manual.

Based on the fact that the oil stopped coming out with the engine running, wouldn't this signify that the oil slinger is doing its job; i.e. pushing the oil away from the seal?

Upon inspection of the gaping hole where the shaft came out, it's obvious that the main bearing has come apart, and also the main seal has melted from the friction of the unsupported shaft. Furthermore, the main shaft is very deeply scored over about a 1" length around where it lines up with the seal and bearing. Due to this scoring, I believe I'd need a new main shaft in order for the seal to be able to seat up against it correctly.

We're currently looking into options, including a new transmission from Gowesty. Ours definitely needs a new main shaft, throwout bearing, main seal, potentially a new oil slinger, circlip, and there's a possibility it'd need more stuff, depending on what I find inside. I also need new axle shaft seals, which seem tricky to replace without the right tools (although I already have the seals). Given all of this, the scarcity of parts, and the long distance we still have to travel, I'm still leaning toward importing one from the USA. Expensive as all hell, yes. But at this point, peace of mind is a priceless commodity. We seem to be stopped every 500 miles with some dibilitating, show-stopping mechanical failure. It's becoming the theme of our trip, which kind of sucks.

I really appreciate the thought and time you put into your suggestion. I'll add it to the list of options. What we really need is a big money sponsor to keep us in a constant supply of new parts!
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PostPosted: Tue Jun 19, 2012 1:59 pm    Post subject: Reply with quote

drivenachodrive wrote:
What we really need is a big money sponsor to keep us in a constant supply of new parts!


Yeah, me too.

Don't worry, you'll get it straightened out. I'm looking forward reading your blog again, it's been a while since I've had time.
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PostPosted: Tue Jun 19, 2012 2:03 pm    Post subject: Reply with quote

As mention earlier, make SURE to get a new clutch pilot bearing for inside the end of the crankshaft. The engine end of that trans input shaft rides in it. It must be damaged, if one is even in there anymore. Get 2 and keep a spare.

Mark


drivenachodrive wrote:
................
Upon inspection of the gaping hole where the shaft came out, it's obvious that the main bearing has come apart, and also the main seal has melted from the friction of the unsupported shaft. Furthermore, the main shaft is very deeply scored over about a 1" length around where it lines up with the seal and bearing. Due to this scoring, I believe I'd need a new main shaft in order for the seal to be able to seat up against it correctly.
...............
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PostPosted: Tue Jun 19, 2012 2:09 pm    Post subject: Reply with quote

crazyvwman, actually when I said "throwout bearing", I meant pilot bearing. The thing doesn't even exist any more. I was able to pull some pieces of it out with my finger, but the thing is gone. Because of its nonexistence, our main shaft became severely scored, ruining the main shaft as well. I imagine I drove 45 miles without a pilot bearing, although it didn't make any unusual noises. A crazy thing to contemplate. Fortunately it ceased to operate only 3 miles from a really great little town with some cheap/sweet cabins, where we're now relaxing in style while we make decisions.
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PostPosted: Tue Jun 19, 2012 2:40 pm    Post subject: Reply with quote

I had similar symptoms when my clutch failed due to transaxle gear oil exposure caused by an exploded pilot bearing allowing the main shaft to move about.
It may just be as simple and crappy as a grease soaked clutch.
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PostPosted: Tue Jun 19, 2012 2:49 pm    Post subject: Reply with quote

So it sounds like all you may need is a good complete bellhousing and an input shaft. Is the small threaded stud still present on the inner mainshaft where the input shaft was supposed to attach? If the real mainshaft looks good and has no sign of play in the inner housing then the tranny may still be good. I can understand wanting to get a fresh complete tranny but it seems like you will spend about $2000 more to do that than if you just replaced those parts that really need it.

It is common enough to swap the bellhousing and input shaft when needed and I have done it myself at least a dozen times. Once was far from home when my tranny blew up internally. I had a spare bare tranny boxed up waiting at home. Without the input shaft and bellhousing on it the tranny is smaller and lighter so cheaper and easier to ship. I had a relative FedEx it to me. I swapped over the bellhousing and shaft to it and was on my way that day.

Mark


drivenachodrive wrote:
crazyvwman, actually when I said "throwout bearing", I meant pilot bearing. The thing doesn't even exist any more. I was able to pull some pieces of it out with my finger, but the thing is gone. Because of its nonexistence, our main shaft became severely scored, ruining the main shaft as well. I imagine I drove 45 miles without a pilot bearing, although it didn't make any unusual noises. A crazy thing to contemplate. Fortunately it ceased to operate only 3 miles from a really great little town with some cheap/sweet cabins, where we're now relaxing in style while we make decisions.
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PostPosted: Tue Jun 19, 2012 2:51 pm    Post subject: Reply with quote

Does anybody know if the input shaft cross-references to other VWs? I want to say I remember this being the same as a late model bus, but I'm not sure.
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PostPosted: Tue Jun 19, 2012 7:23 pm    Post subject: Reply with quote

Brad, first lets agree on some terminology so we know we're discussing the same things.

The shaft that came out in your hands is the pilot shaft. The book calls it the "mainshaft, rear", but lets stick to pilot shaft to distinguish it from the actual main, or primary, gearshaft. The pilot shaft joins the actual main gearshaft inside the final drive cavity, which you open by removing the bellhousing. From there the main gearshaft proceeds into the actual gearbox to do the magic the gearbox does of assisting you in making a mere 100 ft.lbs. of torque make a 6000lb. object move.

The book is actually very confusing on this matter, as they insist on always showing the pilot shaft with the bellhousing in the same picture as if they are inseparable. In reality, the pilot shaft connects to the splined rear end of the main gear shaft as described, by the stud, covered by the splined sleeve, and that is retained by the circlip; all of that stuff is out of sight inside the final drive cavity. Once that juncture is assembled, the bellhousing will slip over the pilot shaft from the rear and bolt up to the main gear casing. But here's where I think you may be getting a little crossed up: when the clutch is disengaged (pedal to the floor) the other end of the pilot shaft is only borne by the pilot bearing in the hub of the crankshaft, so there is no bearing for the pilot shaft in the bellhousing itself. What you see the remnants of there, which I believe you are thinking was formerly a bearing, was not, it was just the oil slinger tube and a small seal.

When the clutch is engaged ( foot off the pedal) the clutch pressure plate sandwiches the disc between it and the flywheel so solidly, that the disc hub provides all the support for the rear (engine) end of the pilot shaft. Of course under that condition the pilot shaft and engine are solidly coupled and turning the same speed, so the pilot bearing is not turning at all. The only time the pilot shaft is actually borne by the little pilot needle bearing is when the clutch is disengaged, then the disc is able to turn at a different rate than the flywheel and it requires the pilot bearing there to keep the pilot shaft and disc running on center.

Quote:
On the morning of
the drive, we stopped and I got out. I noticed oil pouring out of the
junction between the engine and transmission. I turned the engine
back on and the flow decreased to a fast drip. By revving the engine
to 2-3k I could get the leak to stop. I figured it was engine oil, as
it was black. As for why the leak stops under engine speed, I have no
idea. Note that it goes away whether in gear or in neutral.


From this passage and what followed, here's what I think probably happened: the pilot shaft seal was already bad and allowing oil to leak out, but the slinger was sufficiently intact to lead oil away from the seal, which is its job, when the pilot shaft was spinning, i.e. when the engine was running and clutch was engaged. That why the leakage diminished when the engine was running, whether in gear or not (although had you checked, it would have increased whenever the clutch was disengaged).

The little seal may have been wiped out by the circlip when it came off, hard to say, and the evidence of that has been forever lost by what followed. Or perhaps the pilot bearing in the crank hub was failing, and that allowed the pilot shaft to run a little eccentric and that wallowed out the seal.

Quote:
After about 45 miles, while going up a mild hill, it felt like our
clutch went out. We were driving in 2nd gear, and we instantly lost all
power, the engine revved, but the clutch wasn`t engaged. I stopped,
and verified that I could put it in any gear (including reverse), but
letting out the clutch didn`t cause it to engage at all.


That was the moment when the splined sleeve slid back enough to come away from the main gearshaft's splines. the engine quickly screwed the stud in and snapped it, and at that point the juncture that transmits torque from the pilot shaft to the main gearshaft was broken. It would act just like total clutch slippage.

At that point the forward end of the pilot shaft was unsupported (since there isnt a bearing for it in the bellhousing). The only things keeping it in its running line were the pilot bearing and the disc hub. But the first time you disengaged the clutch, the disc was released and could move off center, so the pilot shaft, having lost that support, was able to swing off center at its forward end, and once it ran even slightly eccentric it would have swung wider, wiping out the slinger, whatever remained of the seal, and probably did a bit of a number on the pilot bearing as well, although possibly not because it isn't that tight a fit and would allow for a little angular displacement.

Quote:
We got a truck to tow us about 4 miles while Nacho idled. When we
arrived, I noticed that our clutch seemed to engage again. I didn`t
want to drive far for fear of getting stuck, but I was able to put it
in reverse and 1st gear and get the van to move as normal for a few
feet.


And this is where my scenario shits the bed because I can't come up with a plausible mechanism whereby the pilot-to-mainshaft juncture was broken yet the sleeve managed to recouple them enough that you could do that. But then you're in the land of the brujo and stranger things than that happen daily.

I wrote all this up in order to make clear to you that the pilot shaft didn't destroy the mainshaft bearing, because there wasn't any bearing where I believe you thought there was, there was only the pilot shaft seal and oil slinger there. Which means that once you remove the remnants of those little parts, the bellhousing itself may be perfectly OK, or only slightly marred, and able to have a new seal and slinger reinstalled, perhaps with the aid of a little epoxy or Bazooka Joe. Once you take the bellhousing off it is very easy to repair that area. As long as the splines on the pilot shaft are intact at both ends, scoring of the plain area where the seal lip needs to run can be filled by epoxy and sanded smooth again, if you can't lay your hands on a suitable replacement. Which leaves recoupling the pilot to the mainshaft, which I covered earlier, and possibly replacing the pilot bearing if it was actually damaged, and I would say there is a fair chance it actually survived.

It's all in the spirit of the road, or at least the roads I have travelled, where you have to make what you have work, sending for big expensive parts from far away was never even remotely plausible in my travel realities so it was never a matter of choice, but I would have fixed what was in front of me if it was humanly possible regardless. Otherwise, why would anyone want to listen to my stories?

Once again, best of luck, keep us posted on your progress, you provide inspiration for a time when we can get away and do something like you're doing ourselves.
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climberjohn
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PostPosted: Wed Jun 20, 2012 5:42 am    Post subject: Reply with quote

Three cheers for Tencent for reaching out to a Samba member in dire need. This forum continues to rock.
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