Blinking (D) Drive Light on 1998 Civic

I have a little over 100,000 miles on my 98 civic, and recently when I
was traveling on a 90 mile trip, about half way to my destination, my
drive light on the dash started blinking. It feels like the
acceleration slips and the car has become a bit jumpy. I didn't get the
drivers manual with the car, and I cannot find an answer to what the
blinking D is trying to indicate online. Does anyone know what this
means and what I should end up buying for my car to stop having this
problem? Thanks!!

 

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You could get the codes read, but it's likely the tranny isn't locking
properly. Change the tranny fluid with Honda Z1. Drive it a while and do
it again. Some will tell you to do it a third time. Whatever you do,
don't put anything in it that isn't Honda brand. While you're there,
order the Owner's Manual from the dealer. It's well worth it. You can
change the ATF yourself, or take the fluid to Monkey lube and let them
do it while they change your oil.

'Curly'

 

Let's start with the obvious.

When was the tranny fluid last changed, and is it Honda Z1 fluid?

 

The transmission fluid wasn't changed since I last had an oil change 2
days ago. They checked fluids and said they were fine. I'm new at
auto-maintenance so I will take the tips for granted. Also, if it's
slipping, being the milage I have, is it possible that the transmission
may be nearing replacement?