hi i have a vauxhall astra 1'8 auto 67k on clock. car starts and drives fine untill car gets into 4th gear then a light comes on on the dash and box wont change back up to 3rd gear.its had a new radiator about 5 months ago and had the gear box flushed and new fluid put in . any ideas whot the problem could be ?
If the rad was changed and transmission 'flushed?' due to coolant getting into box then you have a problem. NO amount of flushing will prevent the damage caused by contamination.