85 monte ss shifting problem...

my 85 ss won't shift into overdrive...it just stays in 3rd and feels low geared. i was wondering what could cause this and how could it be fixed. thanks.

Check your vehicle speed sensor...located somewhere around the top of your transmission.

Your monte carlo has a lockup converter. it's controlled by an electronic piece, (not sure where it's located). Here is a list of bulletins and recalls on the 85 ss monte carlo. One of the recalls is on the lockup converter, and converter shudder.

Your monte carlo has a lockup converter. it's controlled by an electronic piece, (not sure where it's located). Here is a list of bulletins and recalls on the 85 ss monte carlo. One of the recalls is on the lockup converter, and converter shudder.
http://www.alldata.com/TSB/10/861007HC.html