Why does My Acura MDX engage into gear sometimes and sometimes not? on 2004 Acura MDX

My wife drove the MDX the other day and said it started to shudder suddenly, and the D5 light started to blink, but she drove home. Now when I start it and put into drive(any D1-D5)it drives sometimes but sometimes it does not engage into a gear. When I remove the dip auto transmission dip stick,it seems to have a bit of a burnet smell. Can anyone make a suggestion to what the issue could be?

Asked by for the 2004 Acura MDX
IF it can make it to the dealer , get it there and have the fluid changed. If you go to an independent shop bring Honda/Acura ATF with you(4Qts.) The 'D' light was blinking because the trans control module stored a trouble code(s). Have that scanned , may be lucky and it's only a pressure switch. If anyone recommends a 'flush' tell them NO, ONLY drain and fill, but they may want to do that 2 or 3 times with a 10 mile drive cycle between them.
Thank you very much. I will try that.