95 2wd auto trans problem

350 in pretty good running order, no trouble codes, good compression on all cyclinders. Seems that it isn't shifting to the next gear when it should under fairly hard acceleration (getting on the highway). There are no trouble codes stored. Engine revs up to 4000 and holds there too long, I back off gas and it will shift. Knowledge abouts trannys is very limited. I have changed the trans filter and fluid. My Haynes manual mentions a "throttle valve cable" off the throttle lever to controll line pressure, shifts points etc, but I sure don' see it (just throttle and cruise). How does this type know when to shift?? Any help you be much appreciated.

Try To Contact A Member By The Name Of Gmmerlin,he's Good At All These Gm Questions He's A Veteran Auto Mechanic

350 in pretty good running order, no trouble codes, good compression on all cyclinders. Seems that it isn't shifting to the next gear when it should under fairly hard acceleration (getting on the highway). There are no trouble codes stored. Engine revs up to 4000 and holds there too long, I back off gas and it will shift. Knowledge abouts trannys is very limited. I have changed the trans filter and fluid. My Haynes manual mentions a "throttle valve cable" off the throttle lever to controll line pressure, shifts points etc, but I sure don' see it (just throttle and cruise). How does this type know when to shift?? Any help you be much appreciated.
did you ever get to the botom of what was wrong with your vehicle with gmmerlin let me know what you found!

Hey back2life,
The problem ended up being nothing to do with the tranny or engine for that matter. If was the inline fuel filter ($6.00 plus flare nut wrench $14.00). Took about 20 minutes and it runs like a champ. I'm just glad I started with the cheapest parts first. Thanks for all the help from forum members.
Jim