Had my 2006 (40k) auto crossfire serviced on Monday. Since then gearbox feels lumpy! Driving home tonight I slowed down and lost gears. Car was revving but in Drive! Fiddled about with the gear stick into neutral then drive etc.. And after a couple of mins in clicked into gear and I was off. The gear box sump gasket, oil and engine oil was changed at the service. I've had the car 3 years without the slightest problem.

Any ideas what might be the issue?