Thanks everyone for your help/suggestions.  I think i have fixed it.  Took out both axleshafts and it appears i put the inner cage in backwards when i had it out a few months ago.I think it was coming out slightly which i think was causing the slipping effect, which could explain why it only happen a few times.  I havent driven much since i pulled it out last time or very hard, i guess yesterday it was enough for it to come out a little and not make a good connection.

Not sure if my theory sounds logical, but that's all i can think could happen.  I drove it up a pretty good hill tonight a few times under hard load and seems ok.  It shoudl be nice here tmw so i hope to take a nice drive and make sure everything feels good.

Thanks, Seth

That was after a "graunching" sound - no slippage until after the CV cage broke and I lost my balls - then total "slippage" as open diff left me totally stranded.  But, depending on how one describes a sound and slipping, it might be....

Mini friends!  Mini rides!

Restored/modified Mini 1000 with 1380cc power unit, 2.95:1 FD, adj. suspension, S discs/drums, 10x5 Minilites, 165x70 A008s, custom trim and matching custom trailer.

Or an inner CV joint....remember yer oopsie Hunter2. 

Jeremy

2004 Liquid Yellow MCS Sport/Chrome Pkg, 15% Alta SC Pulley, Alta Intake, Alta IC Diverter, Ultrik Cam, CM Flywheel/FX200, OBX ATB Diff, JCW Software, 1 Ball Exhaust, JCW Plugs, Powerflex Front Subframe Bushings, Powerflex Motor Mount Inserts, Alta Springs, Alta Lower Control Arms, Rear Seat Deleted, 17 by 7 O.Z. Ultraleggeras, Auto Meter Boost/Vacuum And Oil Pressure Gauges.

Sounds like TWO things - clutch slipping needs adjusting and worn outer CV.

Mini friends!  Mini rides!

Restored/modified Mini 1000 with 1380cc power unit, 2.95:1 FD, adj. suspension, S discs/drums, 10x5 Minilites, 165x70 A008s, custom trim and matching custom trailer.

Perhaps a CV's worn and slipping? Never had a diff pin break, so can't help diagnose by the sound.  Someone just posted a few pics of some really trashed CV innards.

SE7EN

Wanted to get the experts opinions before i started to tear the car apart.

Something seems to be slipping as I go up hills under hard load (occured only in 1st and 2nd gear). Had to nurse the mini up a  few hills today as everytime i went above 2000rpm the wheels seemed to slip (loud banging noise).  My initial thought was the splines on the driveshaft, but the car pulls fine when cruising and was able to get home without it happening again.  Although it did happen once as i made a  hard left only going about 5mph.  

I will be pulling the axles out tmw to take a look at them, but wanted any thoughts if this sounds like anything else..diff,clutch...  I just had my axles out and put new circlips in the inner cv joint and the splines looked fine.  Hoping its something simple that i can fix before the PVGP.

 Thanks,Seth.