BMW Repair Questions? Ask a Mechanic for Answers ASAP
Hello im Rob. A UK Certified Motor Technician assisting you today..
There was a known common issue that caused that type of similiar problem where the transmission pressure required to run it would drop out and causes the clutch pack to disengage hence going into neutral..the issue was the mechtronic bridge seal degrading.this lives above the mectronic unit and the main housing for the transmission housing clutch packs..its quite an involved job and the seal kit is available...
Ok.. You;d be better off seeking a BMW specialist in your area..if it was to be honest as some garages might shy away from such a job..you could likely get the mechatronic seal kit from ebay fairly reasonable..plus you need to factor in new transmission oil,service kit...plus labour you could be in the £400/£500 range typically..