tranny shutter/goes into neutral

So, when I drive under normal daily driving conditions my tranny will shutter in the higher shifts if its in the D position (overdrive). If its in the 4 position it doesn't do it. should I be driving in D or 4 around town rarely getting over 45 or 50?
Also, if I come to a hard stop, if I try to take off right away my tranny is like its in neut. position for a second. Its an 06 Tacoma pre runner sport. I drained the tranny fluid and just about 2 quarts came out, and that's what went in until the overflow start seeping out.
any help will be appreciated.

 

Approx 3.2 Qts should have come out. Did you check it running with fluid between 115 and 130 degrees F I suspect you may be low on fluid there are threads here discussing proper trans fluid change procedures. https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/

 

When was your last engine tune up ?
https://www.tacomaworld.com/threads...th-pics-for-second-gen-4-liter-trucks.289913/

 

I actually haven't done a tune up as I have only had it for a couple months, seems to run good, I have only done an oil change. (speedee lube).