Just took the GT on a 400 mile trip yesterday. I noticed near the end of the trip when stopping at a light or slowing down, the auto trans in my 06 will roughly downshift into first. I believe I read that sometimes after hard use the atf will decrease and cause this, but I can't see how this is possible. The car is race tuned with 4.10's and has 31,000 miles.



Any ideas what could be causing this. I believe it is directly related to the 400 highway miles in and through NYC down to NJ. Upshifts are perfectly smooth, no issue, just the downshift into first. Also read it could be something with the driveshaft?



Thanks