300SD Transmission?

[Driver1337]

Just recently within the month, if I start up my car and go, and let the car run up to 2600RPM the engines rpm would jump up and down about 100rpms but the car still accelerates, but it doesn't happen if I let the car warm up. When I come to a complete stop at an intersection or so the car would go into neutral and when I try to accelerate the transmission would catch and jump forward. Also ever since I had it, if I am driving down the road, I can drive at 20mph and then rev it up to 3500RPM and keep it there, the car will continue to accelerate forward and is this normal? I have a 83 300SD Turbo with a OM617.951 and the Automatic 4 speed.