2004 mustang gt 4r75 trans

[jk66]

I was wondering if somebody knows this. I'm replacing the trans in my 2004 mustang gt. it's the 4r75 trans. I'm being told but the company that sold it to me that I need to update the ecm. What is that for, because I don't believe you can update these ecm like the newer cars am I right? I did read somewhere a while back that you don't actually update anything but you just clear the ecm and do the relearn with a better scanner type tool is that right or can someone tell me ?

 

[Yel2002GTAuto]

The 4r70w and 4r75w has one main difference...the tooth count on the sensor wheel is different...there are aftermarket products that can take care of this I believe...I couldn't tune it out before so just had the original tranny rebuilt ...it is some type of speed cal needed to adjust this... not sure if the after market computer like the squirter can adjust this in the programming but that may work as well..

Ed