I too thought the slave could possibly be stuck with the piston extended,... As mentioned by another, not very likely, but stranger things have happened.

If this "arm" broke, I could imagine broken or bent peices of it causing such a jam up.

Hoping it's something simple....

 

I checked the slave cylinder and it is operating normally. It was worth checking.

I'm still trying to find the time and enthusiasm to finally remove the thing...soon

 

Okay, after finding the enthusiasm, I finally removed the thing again. Nothing catastrophic in there, as expected. When I removed the flywheel and put it on the bench there is a fair amount of movement in it, similar to this, without the pressure plate dissaster:
I got a new stock Luk replacement and to my surprise, it also shows some movement. I still believe my old flywheel is the culprit and tomorrow I am going to clamp it down securely and really test it. I believe i will be able to fully rotate it and if so, that would be the cause of my problem.
I will not put it back together until I am 100% sure of the problem because I will not be pulling this tranny again for a long time!
Any similar experiences?

Also, there was a small amount of gear oil in the bell housing but it had collected at the bottom. I figure it is coming from the input shaft seal and has blown out and down to the bottom of the housing. There was little or no oil around that seal though.
Thoughts?
The engine rear main seal is dry and the leak is definitely gear oil.

 

So now that the tranny is out, when you put it in gear and turn the input shaft by hand, the axel shaft flanges rotate, right? I think one should turn forward while the other turns back, or you may have to hold one axel flange so the other will rotate as you turn the input shaft.

Sounds like you found the problem with the flywheel (maybe) and will try to prove that out tomorrow,... Just thinking of a way to prove that the internals of transmission are not a culprit.

 

Yes,

Everything on the transmission seems fine. It's hard to figure which gear is which using only the linkage to shift but rotating the input shaft by hand results in the output shafts turning at different ratios depending on what position the linkage has been set at.
I will be thoroughly checking out the flywheel this morning.

I securely clamped the ring gear portion of the old flywheel to a bench and used a bar between two of the dowels try and spin the other part of the dual mass against it. I could turn it maybe 30 degrees each way before the resistance stopped it. I figure I was putting only about 150 ft/lbs to it. I know that's not a lot compared to what the engine puts on it. I wanted to see it spin which would account for my problem but I couldn't get it to do that.
This car is not going back together until I am 100% sure I am fixing the problem and I don't know that right now.

 

150ft/lb isn't too far from the peak torque of these engines. Unless you spun it up and dumped the clutch the flywheel shouldn't see much more that that. I honestly would think the flywheel is designed in such a way that it cant fail catastrophically like the video describes...

30 degrees is a lot though.

 

If you have a R50 them its your differential. In the R50 the ring gear is pressed on to the differential housing not bolted to it like the other models. All the 5 speed transmission have the same differential. Only the 6 speed tranny have the conventional bolted on ring gear. I know this because I have R50 and the same thing happen to me. No movement in any gear. Mini mania have thee part for about 3 to 4 hundred dollars. You will need to completely clean out the tranny because of the medal particular from the damaged ring gear. I hade 198k on my tranny when it happen. Hope this helped.

Sent from my iPhone using NAMotoring

 

Thanks for the continued input.

I'm reasonably sure I have isolated the problem. The bad news is it's not an easy fix.
I put both drive axles into the transmission with it sitting on the garage floor. I slipped the clutch disc onto the input shaft to give me some leverage and with the tranny in gear, I turned the clutch disc. With no resistance to the drive axles they each turned with the disc but when we held the axles I was still able to turn the disc and stop the turning of the axles. It did this in every gear including reverse.
I think this accurately accounts for my situation. Obviously no turning of the wheels when in gear but it would also allow me to shift gears with the engine running and without stepping on the clutch because there is no real connection between the transmission and wheels. The all synchro transmission would shift easily under these circumstances.
Mine is an R53 so I assume it is the bolted on ring gear. It seems awfully hard to find info on the inner workings of these transmissions.

I did find a Youtube video on the installation of a limited slip differential and splitting the transmission case doesn't seem too bad and it gives you a great look at the innards which I must see now.

I've come this far...

 

If anyone is still keeping track of this, the mystery is finally solved. It was the driverside axle after all. Not until I split the transmission case did I figure it out. When I did that I found some metal chips around the driver side output splines. That drive axle has a clip on it that keeps it from sliding out once it has been installed. I never pushed it all the way in so it was only engaged by a small portion of the splines. It was functioning fine until I got on the gas too hard and the splines that were engaged disintegrated. It was hard to see the damage by looking at the axle splines because such a small section were stripped and it looked quite normal.
I suppose all the dismantling that I did was needed because I was able to flush out the tranny case and remove the chips. I am surprised I was able to bolt everything together with the axle improperly installed like that.
Anyway, It's fine now and I put a Valeo clutch/flywheel setup in it. I wasn't going to take a chance with the worn dual mass flywheel.
To think that the first two suggestions were to check the driveshafts. That's what I did and that's what it turned out to be. Live and learn, I guess.