My car had a reco auto transmission fitted for the previous owner not too many kms ago and has worked well since I have had it. Recently, however, it seems to have developed a fault. The car seems to hold back a bit on changes, actually feels like the car is in neutral, before grabbing and 'clunking' hard into gear. Happens from standing starts such as traffic lights. Seems to change down ok. Fluid levels are good and oil is clean. Last week i stopped the car, turned it off then started it again and the problem was gone. Today, after not having driven it for a week, it did it again. On this occasion however, the engine light did NOT come on. Last time it did. Car is a VR V8 Calais. Babied, never driven hard. Any ideas?