I recently bought a 1979 300D automatic. The previous owner had the transmission rebuilt about a year ago, and I have the record for it. I didn't notice it before buying it, but now I'm positive that my car is not using first gear. I start in second, and end in fourth. One might be able to imagine how hard it is to climb a hill from a dead stop with this problem, which is something I do many times every day. If I stop, I can put the shifter in L and the car drops into first gear. Then while at the same stop, put it back in drive, and it'll take off in first. Does anyone know why this happens? I'll take it to a mechanic, but I'd like to have some ideas first as to what to expect.