I have a 91 nonturbo with an automatic and i am not sure if it is shifting into overdrive. I dont think that it is. In the supposed OD the tach reads right at 4000rpm at 70mph. somebody please help me out here is it in 3rd or 4rth

 

could some body with an auto tranny help this brother out? come on guys, i know there's oughta be one or two auto owners in here somewhere....

 

Assuming that you have stock sized tires, according to the gear ratio calculator:

205/50/16 tires, 3.90 rear end

3rd gear (1.0:1) at 70mph: 4000RPM
4th gear (.72:1) at 70mph: 2900RPM

So based on that, assuming stock tires, you're right, your OD isn't working.

 

Does overdrive have a fuse?

 

If he is still on stock wheels and tires it is 205 60 15. Think you put the T2 numbers in but he said he has a NA.