Toyota Repair: 93 4 runner overdrive problem, coolant temp, clutch packs

Question
My 19993 Toyota 4 runner wont go into overdrive until it gets really warm. Have to drive 10 miles prior to going into overdrive.  I've removed the solenoids in the valve body and energized them they all work also replaced the orings. Ive checked all the grounds and power to the ecm. The coolant temp sender is new as well. Does this vehicle have an overdrive relay? Its not where all data claims its at (behind the instrument cluster). Or suggestions valve body? Thanks Tim

Answer
There is no overdrive relay, just the o/d solenoid.
This is an indication of an internal hydraulic pressure loss which means the transmission has an internal leak due to worn seals or clutch packs, the transmission needs to be overhauled or replaced.
My 1990 4Runner has been doing the same thing (256K) but it normally goes into O/D within about 2 miles unless I let it warm up for about 5 minutes, then no problem.
I kind of learned to live with it because I don't look foreward to overhauling it or replacing it even with a used one(about$1,800)I also noticed that on hard acceleration from a stop it will chatter, this is definetely a transmission problem but I don't drive it much anymore but eventually I will have to deal with it.
In your case it seems a little more severe if it takes ten miles to upshift so I would recommend getting a good used trans, rebuilding this one or trading it in.