Chevrolet Repair: 700 R -4 Transmission problem with shifting, throttle linkage, chevy c

Question
I have a 1986 Chevy C-K 4X4 drive pickup.I have just put a used transmission in it because the other one went out. This trans shifted the first time I drove it down the road. But it would not shift on the way back and has not since.I have put a new D-10 cable on it and new governor. But it still will not up shift. This is a 700r-4 trans.Is there anything you could tell me that might help.This trans was suppost to of been rebuild 15,000 miles ago. (Thanks for your help). Sign Dan Frank

Answer
Hi Frank,
I think you mean "detent" cable, or throttle cable. Are you sure it is connected correctly? You can pull against it at the throttle linkage, and should feel spring pressure. Let go, and it should snap back. Might try that a couple times. The valve it is connected to, much like a kickdown valve, may be stuck in the pulled position, which would be like kicked down.
If the transmission sat for a period of time, that is sure possible.
See if you can't get it to snap back in, and go in further.
You could leave it disconnected, and it just wouldn't downshift when you floor the throttle.
I immagine you floored it when you turned around, and it stuck.
Let me know what you find. May possibly need to drop the pan to loosen tha valve up.
Good luck,
Van