when starting from cold it selects all gears fine , as it warms up to normal temp it stops going into 1st when stopping meaning you need to select 1st manually to pull away otherwise it starts in second . then just tonight I went to select reverse and it would not go in. after leaving it for approx. 3 hours I had to go home and it went in to reverse no problem until I travelled about 1 mile then it refused to find reverse again ! it had a new filter and oil 2 year ago and has been fine until now, I dropped the oil out ( sump content) at the weekend hoping some fresh oil mite help but just seems the same , whats puzzling me is it works fine when cold ! any ideas anyone ?