When replacing my kickdown-cable for a new one I noticed that the detent valve is stuck, no movement at all! It is the axle with the hole in it where you attach your kickdown-cable in. That explaines why it wouldn't shift to 2nd. The car had not moved for a year or 8 (longrunning project

I'm afraid this can only be fixed by opening the transmission? But I don't think I can reach it when removing the sump as it is placed on the upper side of the transmission.
Anyone with a solution or tips?
Thanks Jasper from Maassluis/The Netherlands