Hey scotty i just wastched a genious and really easy way to check for ground problems u posted. First off thank u brother! I have a 2003 ford ranger 3.0 2wd edge. My bro in law drove it n said it would hesitate sometimes but with a quick twist of the neg cable all would be well again. I bought it n replaced the end but didnt cut the cable back, but rather just cleaned it. I got a feeling ill find the other end of the cable is also ugly. Also the tranny was over filled a half quart which i immediately siphoned out. Prob due for a flush but not too bad via rag test. Can a ground problem affect shifting? The way it acts could be engine not pulling or tranny not engauging and its rare. I havent yed did the ground check. But is auto trannys also controlled with electronics that could be affected? I put it to the floor it spins tires and gets moving. It only does this at low rpm under little stress. Thanks!

yes it can, replace the entire cable really. But also realize those have weak trannys and it could just be going out be 15 years old