Just bought a 1990 350 SDL which has been sitting for a while. The 4 spd auto trans works well in revesrse,2,3,4 but never goes into 1st when stopped. Is this a valve body or linkage problem? I have rebuilt tranys before, this sounds like a valve stuck which won't allow shift to 1st, but the $$$$ MB CD shop manual I bought, for some strange reason has no section on transmissions. Where can I obtain a diagram of valve body and or info on MB 4 speed Auto trans? I can do the work, but have no Idea of specs or whether trans has been apart and someone dropped a small steel ball on the floor and didn't replace in the proper hole, then wholesaled car because of the problem.. loneranger