I have a 2012 Honda Civic LX that was purchased new in 2013 and since I had no major mechanical issues owning the car. Today I went out to go grocery shopping and I leave the parking lot and put the vehicle in D3 as I was driving an uphill road. I stopped at the red light at the top of the hill, while i am in D3 mode and I decided ill just switch to D since its now flat road. So I am driving on the flat road and I switch from D3 to D without stopping the vehicle at speeds of 20-25mph mph and for criky sakes the car jerked as if someone hit me behind. I was pretty damn scared thinking my transmission is now toast. I pulled over and parked the car, then switched to N then switched to D and jerked again.

I am thinking oh golly what i have done now. I put the car in R and there was no jerk motion. I put back to D again and jerked again. I was so worried that I might need to rebuild this transmission and thoughts came to my mind that I have to now tow the car and not having a car for week.. All I wanted was just to grab some potatoes, drive home and cook some mash potatoes and gravy dinner and watch some SNL. I then decided to turn the car off, locked doors and took a walk around the neighborhood. I came back five mins later, turned the car on, switched to D and it was smooth as butter. Took it for a drive on a 25mph road then on a highway to see if its OK and going at 65mph there was no issues. I arrived home switching from P to D, N to D and vice versa, no issues at all. Did I confuse or glitch the automatic transmission module/system by accident? Turning off and on the vehicle reset the computer it seems.

Is it usually safe to switch from D to D3 as long as your traveling low speeds 20-25mph?

 

Shifting gears is fine.

Check your ATF?? When was is last changed?

 

I had my ATF changed at 100k at the honda dealership. The vehicle is now at198k miles and I also been thinking to change the spark plugs and oil, PCV valve? flush brake fluid, coolant fluid. I also need to put a new carpet since the driver side has a large hole from my sneaker heel and ripped the carpet to shreds..
Good idea, its time for maintenance this spring.