What about dish soap?

I used to wash my parents' cars with an auto sponge, a bucket of hot water and good squirt of dish soap in there. Got the cars amazingly clean. Before I started using Simple Green I would use hot water and dish soap. I just dipped a rag in the bucket, wrung it out, and wiped down the frame. Then I rinsed the rag in water only and went over the frame one more time to get all the residual dish soap. I haven't tried it on greasy drive train parts though. I wonder if that would work...