[Shadows335i]

I have a 2009 335i with the mhd stage 1+ 93 Oct tune, and I've been experiencing some rather troubling things coming from my rear axle. When I'm taking off from a stop, go through first gear fine, get into second gear and it feels almost like the back right tire (passenger side) is breaking traction. But I'm not getting the D.S.C light flashing as it should, it just shakes the car really bad and up shifts to third. But just like a half hour ago, I was driving got on it in second gear and it poped out and into first and my tach shot up over 8000 rpm. Immediately slammed the breaks and dropped it into neutral, pulled over put it in park heard and felt my trans thump and then drove off again like it was fine. What could be causing causing this.

Codes?

Miles?

Was the car tuned prior with anything (JB, etc.)?

When was the last time you changed the fluid/mechatronic seal? Is it leaking?

Aside from that, given the "pop out of gear" scenario, I see some major part swaps and/or maintenance in your future...

[Shadows335i]

No codes or lights

1226xx

Not that I know of got the car at 89xxx miles

Unsure of any transmission services I've had the car for a little under a year no leaks though