Coolant Expansion Tank AT Thermostat
 

I recently did a coolant overhaul on my 2003 X5 3.0. Waterpump, thermostat, upper and lower hoses, belts, coolant temp sensor. Next day, my coolant expansion tank sprung a leak. Changed tank, cap, water outlet pipe from expansion tank to trans oil cooler and also changed the AT thermostat. Since replacement of the AT thermostat I noticed my tranny performs a lot better. Shorter shifts, better pickup off of standstill and a weird vibration for about 2 seconds between 1st and 2nd gear at takeoff has disappeared. Is it just me or has replacing the AT thermostat improved the driveability of the trans?:bmw: