owned the car for 2 yrs. replaced coolant fans after overheating last autumn car does `nt get used very often, recent journeys( low mileage 40 miles tops) yesterday travelled 25 miles, after 20 miles gearshift seemed to tighten up , it`s the tightest shift i have experienced,on any car even before this problem, arrived home and exhaust emission light was on dash, noticed when turning ignition off. after a few hours light still on , this morning started car and light went out . could it be lack of oil in gearbox,? no sign at all of leaking oil, need to know where filler plug to check oil level, any suggestions gratefully accepted.