Hi guys.
I have a 88 Volvo turbo automatic. It used to drive very smooth, except the slightest jerk when it went into 2nd gear. All of a sudden, now it seems like when I am going 50 or more it either stays in 3rd gear until I depress the accelerator (my uncle told me how to do that) or it will shift into 4th gear on its own but when I slow down to like 40 or so I can see the RPMs go up to 30000 and it feels like it drops back to 3rd gear. It may or may not go into 4th gear when I increase my speed after this happens. Considering this is a 16 year old original transmission I'm not surprised, but I'm trying to keep from getting jacked when I take it to a repair shop to ask them to find out what's going on. Is there something I can check or replace prior to going there or at least something I can know when I go in there so they won't think I'm a total idiot. Also I put some transmission (LUCAS) lubricant in there about 3 months ago but it was running fine up until two days ago when I noticed this problem. I saw something about a overdrive relay which I think I have when I pulled a bunch of them from some wrecks at a pick and pull.