I still service one 7FGCU15 with 27K hours. The other one got traded in. When I run into transmission problems I try to made darn sure I figure out what's wrong before taking it out. If it's not moving, check solenoids for power. I'm pretty sure you can feel the magnetism with a small screwdriver and hear them move the spool when they operate. I'm not too familar with what else can go wrong in the control valve other than the solenoids and spools but pressure checks at the F and R clutches would comfirm that the control valve is working and supplying pressure to operate the clutches. One of the Toyotas did have a trans problem but it was from bad operator abuse. They road the inching petal and let the F clutch slip at full throttle until it overheated and warped. That caused it to drag and the truck would want go forward even while in neutral. rick c seems to be a wealth of info on Toyotas, I'm just a independant repair service that works on a bunch of them. I get along well with my local dealer and they help me with any parts pictures and service info.