Hello sounds like a clutch problem to me,without seeing the car cant be a 100% certain.
I rebuild gearbox,s for a living have done for over 10 years now,this gearbox has ep80/90 oil in it which is too thick for the synchromesh,so i always put 10/40 engine oil in them,it wont do any damage or cause any problems what so ever.
Richard
rbtransmissions@aol.com
Richard
May 2006