Bmw 530d automatic tranmission issue

[Ross.baker]

I have a 2008 530d with 130000 miles, in 1st and 2nd gears the revs rise to 2000rpm and stay there til its gets to 3rd gear where its starts to drive and shift normally, when started cold in the morning it will do it in all gears but soon after a couple of minutes will go back to just the first 2 gears, i have taken it to a gearbox specialist who changed the oil but has made no difference.