'96 Taurus won't shift into OD

Hello,
I've got a '96 Ford Taurus 3.0 V6. The tranny will not shift into over drive. Even on the highway at speeds of 70 mph, it won't shift into o.d. Also, for quite a while prior to this, the "Service
Engine Soon" light has been on.
The car shifts nice and smoothly and I haven't noticed any problems with the tranny other than the o.d. problem.
Any idea's what might be causing this? Thanks in advance for your input.
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snipped-for-privacy@gmail.com wrote:

When the Service Engine soon light comes on that usually means there's a problem... maybe even the one you're having.
MOST people go to Autozone or other part store to have the codes read out.
Bring back the code # , not just the 'definition'
--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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