Mercon V is a full synthetic and ford says specifically to use that exclusively. I live in AK so synthetics are a big deal hear so I wanted to do the mobile "arctic gear oil" switch. so upon talking with 3 trany shops that said if i like my trany and my warranty don’t, and well ford said mercon V only or wave by to my warranty. To expand on the trany shop point prospective all 3 shops said it “can” be done but it is not wise. Although mobile meets the minimum mercon requirements it is not a quality substitute in any way shape or form. Plus mercon is a full synthetic how much more will you get with another form of synthetic. ? I not saying any one is wrong please don’t take it that way, I only wish to share the facts and risks involved. And to the hole safe with it being the same red looking fluid, for your sake I hope you have a dumb shop because even at the base car shop we have these thing like litmus strips that after we dip it in your oil we can stick into a computer and it will tell you what type of oil it is and apparently down to the manufacturer based on additives, so i find it hard to belive that ford cant do the same.
As far as sound maybe I have been driving old nosy tranys to long but, my stang trany is way quieter than my 85 F-150 with a BW T-18. My dad has a 92 F-150 with a Mazda 5sd OD and that was the smoothest and quietest trany I have ever driven till this car. So if you are getting that much nose I would say you have a issue. My dad had a similar problem back in 98 with his truck after a clutch swop and it turned out to be the clutch we put in was all the same but for some small detail and it had been boxed wrong lol. It took us 4 weeks and 900 miles to sort that mess out, and all along people told him that was a normal noise till they heard it. Point being only you know you car, go with your gut instinct and fallow it.