Ok I'm brand new here and need help asap please. I just bought a 2000 v6 mustang for a daily driver, the trans went out on me so I bought a 4R70W that I was told would work, well its installed now and the speedo is wayyy off so its throwing a P1270 code. Well i have done a little bit of research since then and realized that the gear that the oss sensor reads off of is not the same. So my question now is what is the best way to correct this problem? What kind of tuner can fix this if that is a possibility? Is there a TCU in these cars? will the TCU from the 2004 car work in mine and fix the problem? please excuse my ignorance here but I just need advice.