Funny noise car won't go forward ,speedo goes up though

[AL92]

Was doing some hard test and tune on my 91 fwd turbo. Then heard a bang and then no forward or reverse motion..nothing..car was fine shifting fine,clutch fine..tranny fine..
I did have car at shop checking it out earlier and took off cat converter.We noticed a ripped axle boot.
We towed car to shop and then put it up and the wheels started to spin again..!!
Then put it down and shop guy drove it gently around parking lot.I then took it out of lot and went about two blocks..heard another funny noise from front of car not sure what side and now no forward or backward but again the speedo goes up but car don't move.Looked at shift cables and they seem fine.
So how likely is it have busted axle problem and how come it worked for a few minutes again and then went back to no forward or backward motion?
Also are aftermarket jobber axles as bad as I hear and any good makes of them out there.
How much are fwd new axles from mits/dodge/satan?
or should I change it with wrecker axles?
I am selling the car but don't want to give the next guy a problem.
I won't know that much more till monday when shop can take another look.I can't see how it can be clutch or tranny its shifting like butter and we were only running 10psi or so .Engine is fine..

 

[Ultimatedsm]

Samething happend to me when my two piece axle bolts that hold it to the frame broke off. The axle came out ruining the seal and leaked tranny fluid everywhere. Once that happend, my car wouldn't move, RPM's would climb but the car would stay with a funny noise I remember. I can't describe the noise exactly because this incident was YEARS ago . If you have a broken axle, the sympthoms would be the same. I got an aftermarket axle and has worked fine ever since (replaced axle due to it being siezed into the hub), I have done many AWD launches on it and never broke yet which is a good sign . OEM is always the best way to go, however, I noticed aftermarket shafts are pretty good as well. Do not get a wrecker if you don't want to give the next guy problems, who knows how long it will last before the boost rips or axle snaps. Anyway, good luck with the car and I hope this helps.