Sudden Transmission issue, slipping

[Chad800xt]

Hello everyone,
I am new to the forum but have been reading posts for a long time, this is my second x5 and this forum has helped me many times already...
My issue...
I have a zf-5hp24 in a 2002 X5 4.4i 160km's, only had the vehicle for a month and don't know the maintenance history. Been driving and shifting great up until a couple days ago... First odd thing I noticed was A brief shutter between shifts during soft acceleration, I'm thinking 2-3 gears, only lasted for a second as I let off the gas and then it resumed normally, did this twice on 2 seperate occasions. Next day I got in the car and when I put it in park I noticed a delay before it engaged, was longer than normal, maybe 3 sec. After that everything was normal. Next day, after drifting about 5 mins, make the corner and go to accelerate and the trans slips, the rpms jump about a 1000 and it lurches into gear and forward... Resumes driving as normal FOR 5 min. Then she does it again, this time with a squeel when it grabbed the gear, does it on the very next soft acceleration and "FAIL SAFE MODE" appears. The trans goes to 4th or 5th and I limp it a couple kms home. I left it alone for the night and this morning I investigated further, starts with no fail safe mode, CPU throws no codes and it appears to shift ok under soft accel, if I punch it a little I can tell it's slipping a little and makes a bit of a squeel noise. Only drove it around the block and now it's parked until I can resolve this issue. I am very mechanically inclined but have little knowledge of the internals of automatic transmissions and even less about the ZF ones, any input would be greatly appreciated.
Thanks, Chad.