86' Firebird TA- speedo quit / trans won't shift..help!!



Speedometer quit, and at the same time trans will only shift into 1st, 2nd, N and R.
Tranny only has 1900 miles on it (built 700R4).

Where should I start; fuses (any hidden ones I may not have known about), bad PCM, speed sensors. I don't think it's the tranny itself, just seems odd the speedo quit and the trans locked up. Any help appreciated?
Last edited:


the same thing happened to me on my 87 but I lost reverse drove it for awhile just pushing it backwards then I lost 3-4 and dorve it for a while with just 1-2 gear for about a month then I lost those ......the hole time trying to find out what was wrong ....nobody knew and all I could get from any shop was to bring it in.so I wish you the best of luck If i find out any thing I will surly let you know. Darron


New member
is it electronic? if not its probably the govenor on the transmission, this relies on a speed signal from the speedo to determine when the transmission shifts. Now electronic transmissions uses a vehicle speed sensor instead of a govenor. doesnt do anything that the govenor didnt do but make it alittle quicker and better.
Your email address will not be publicly visible. We will only use it to contact you to confirm your post.