Car sometimes jolts quite hard when shifting from 1st to 2nd gear. This only happens when the car has been sitting for several days and is more likely to happen when it is cold outside. Once or twice on extremely cold days it struggled to get into 3rd, but MUCH less pronounced. Yesterday, after the car had not been driven for 1 week, it failed to shift up into 2nd gear at all and chugged hard while stopped at red light (as though it was about to stall). The check engine light came on and off a few times (I managed to crawl back to parking space in 1st gear). Warmed car up this morning for 5 minutes and reversed back and forth twice before driving it to mechanic with no problems - shifted smoothly, accelerated normally. Mechanic had no problems during road test, says fluid levels/quality are good, no problems indicated on computer readout. What could be going on?
My car has 77000 miles.
My car has an automatic transmission.
Many newer automatic transmissions have temperature-sensors in them that, on a stone-cold start, restrict normal shift to only the lower (or non-overdrive gears) until the engine coolant and transmission fluid reach a certain level which in many engines, is around 140 degrees. At that point, engineers generally consider an engine or transmission fully warm for fluid-circulation and engine-stress purposes (this is usually at the lower end of the normal range on an analog temperature-gauge, or when the blue cold-engine light goes off). In some cases, this temperature sensor may fail resulting in delayed shifting or erratic shifting. I would suggest having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.
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